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No way! Why am I a spider!?

"Well, though I hate to admit it, I've been reincarnated as a spider."
Chapter 1
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Kumo desu ga, Nani ka? (So I'm a Spider, So What?) is a Web Serial Novel series written by Baba Okina. In an alternate world, as their final act, a great Hero and Demon King unleash a cataclysmic magic. Said magic tears through dimensions and erupts into a Japanese high school classroom, killing everyone inside instantly. But instead of staying dead, those present find themselves reincarnated into the alternate world.

In a subversion of the usual "reincarnated into an RPG universe" story, our protagonist is a quiet, lonely girl who is reincarnated not as the next Chosen One... but as a spider. No, not a Cute Monster Girl spider, but the lowest level of spider monster Mooks, that you would kill in a starter RPG cave. Now she has to use all her wits in order to survive in the world's deadliest labyrinth.

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The series has been adapted into a Light Novel and Manga, both of which have been licensed by Yen Press.

An anime is in the works and a PV of the series can be viewed here.


This work contains examples of:

  • Accidental Murder: In the Light Novel, the first time Kumoko killed someone it was an accident. While she was pissed about them torching her home and decided to punish the group responsible, she didn't expect briefly turning her evil eyes on them would be enough to kill them instantly. Afterwards she just goes 'Oh, hm, they're worth a lot of exp, they started it and in for a penny, in for a pound, right?' and kills the rest.
  • Adaptation Expansion: The light novel adds a significant number of new scenes that were not present in the web novel, such as the inclusion of a massive snake monster being killed by Alaba to set up Kumoko believing she couldn't take him in a straight fight, so she uses Sloth instead. It also reveals some information early on that was intentionally kept secret in the Web Novel such as her plan to eat Mother The manga takes it slightly further than that and spoils the presence of Ariel and the Mind Rape effects of Taboo.
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  • Adaptive Ability: A part of the skill system. Hit an enemy with enough non-lethal fire strikes and it will start developing fire resistance. Same goes for other elements, poisons, magic, psi attacks, or even straight up physical damage.
  • Adventure Guild: Exists in-universe though largely out of focus. Ariel maintains a membership so she can take advantage of the perks while traveling.
  • Aerith and Bob: There are names like Sophia and Ariel and then there are those like Gyuriedistodiez (usually called Gyurie) and Merazofis.
  • The Ageless: The staggeringly expensive Immortality skill. Though you'll never age or be killed by anything inside the System after buying it, you can still be killed by being removed from the system. As Kumoko realizes after gaining it via evolution, only to lose her current body to Ariel's System expelling Abyss magic. Also, if you lack a regeneration ability, you can potentially be crushed into a paste and still be alive.
  • Always Someone Better
    • As Shiraori tells Sophia, she's weak, little more than prey unless she becomes strong. But even if she becomes strong, there'll be someone else out there even tougher that can still wipe the floor with her. The only way to be safe is to be such a big fish that no one can hurt you. Shiraori herself is at least ten times Sophia's strength and yet is still only something like the fifth biggest fish around behind Gyurie, Sariel, D and Meido, all of whom are mid to high ranked gods. Though Gyurie is a smaller fish that she realizes.
    • Shun was starting to think he was hot shit because everyone treated him like a genius, though he stayed humble about it. However, his failure in the elf village and seeing that Shiraori's group didn't even consider him an obstacle made him realize that he was actually something of a small fry. He resolves that he needs to get stronger and have a better grasp of what he can do and how he can do it if he wants to carry on Julius' will.
  • Amusing Injuries: Since Sophia can survive at least one fatal attack per day regardless of source and isn't a particularly sympathetic character, Shiraori tends to find it amusing to kick her so hard that she nearly snaps in two when annoyed. If it doesn't kill her, great! If it does, she'll come back to life anyway.
  • Anatomy of the Soul: As the story progresses it's revealed that many skills directly affect the soul, such as Parallel Will splitting off a portion of the soul to create two minds. This leads into The Reveal that skills are all modifications of the soul and skill points are the soul's excess energy. When a person or monster dies the skills and skill points are converted into energy; a portion is given to the killer as XP while the rest is absorbed by the System.
  • And Man Grew Proud: The very existence of the ancient civilization has been all but forgotten. Most of the remaining knowledge of it and its destruction is contained in the teachings of the Goddess Religion as Sariel was the one who saved what was left of the world.
  • And Then What?: Felmina asks Sophia what her plans are once the System is destroyed; Sophia realizes she had none. Shiraori's own answer isn't much help for the other reincarnators.
    Shiraori: ...run away.
  • Angst? What Angst?: Invoked. For basically her whole early life, Kumoko has a rather blase and cheery attitude about life in the Elro Labyrinth, seemingly taking everything in stride. She even remarks at one point that she should be traumatized after something that just happened but realizes she isn't reacting emotionally. However, as Shiraori, she gets drunk often and has a habit of telling people at length how horrible the place was and how often she thought she was going to die, indicating she actually was traumatized by her upbringing but simply lacked the emotional awareness to process it properly.
  • Anthropomorphic Food: "D" makes some Valentine's day chocolates, which moves around and wails yet still tastes like chocolate. Even Shiraori won't eat it.
  • Anti-Magic
    • The underground facility has an anti-magic field that blocks any spells and most skills, which themselves are applications of high level magic. It's possible to partially negate this field by copying the anti-anti-magic field the security robots use.
    • Gyuriedistodiez and other dragons of his race can produce anti-magic barriers capable of suppressing even other gods. Potimas reverse-engineered their barriers to create his own anti-magic.
  • Armor-Piercing Question: When Sophia is seemingly completely unrepentant for her mind controlling of the students and teachers at school to feed her hunger for blood no one seems to be able to get through to her. Merazofis steps in and she thinks she has a new ally... until he slaps her and asks her one simple question.
    Merazofis: "Ojou-sama, would your parents be proud of you as you are now?"
  • Ass in Ambassador: The man sent to convince Kumoko to leave Sariera was rude and domineering, which of course made Kumoko avoid him at all times. She later speculates he was chosen specifically because he was likely to cause an incident that could be used as grounds for a war.
  • As You Know: Generally averted. Kumoko will think to herself when she figures out some new mechanic within the System, but if it's something she already knows but didn't discover onscreen she generally won't mention it even when talking to another person about it. The reader doesn't learn what happens at Taboo 10 for a long time, only that it causes Kumoko to briefly go on a murderous rampage out of disgust with humans. The only detailed explanations from someone who knows things is when they're talking to someone who doesn't.
  • Attack! Attack... Retreat! Retreat!: Kumoko was doing pretty well hunting Elro Ferects until she found their nest. It's even in the chapter title.
    Chapter 23: I'm sorry that I got carried away. Please forgive me!
  • Attack of the 50-Foot Whatever: The Myth Class monster Fenrir and Kumoko's "Mother", the Queen Taratect, are huge compared to humans. The Fenrir is even described as the size of a mountain.
  • Awesome, but Impractical: Abyss magic is extremely powerful and seemingly cannot be blocked. However, it's also so complicated that it cannot practically be used in a fight and is barely usable at all. The area of effect on some of the spells is also very dangerous. Kumoko gives up on it after one use while Ariel suspects that it was never intended to be used as a means of war but rather of execution: Death via abyss magic boots the soul of the cycle of rebirth and turns it into mere energy. This is the second reason Kumoko never bothers with it again: Anything killed by Abyss Magic grants no exp.
  • Awful Truth: Level 10 Taboo reveals the actual nature and history of the Skill system: humans destroyed the entire planet centuries ago by creating Life Stream eating MagiTech. The System is essentially a purgatory placed upon humanity where they must fight and die over countless lifetimes to restore the energy they stole. The alternative is letting the world die, killing everyone and rendering every sacrifice up till that point by the comatose goddess Sariel and all the people who died basically pointless. Most people go crazy to some degree after learning this. However, it's less the fault of humans than the Taboo skill actually implies, which is suggested to be intentional on the part of D.note  Taboo doesn't tell the full story but instead emphasizes the recklessness of the humans and their selfishness towards Sariel. When Shun hits Taboo 10 as a result of Shiraori's manipulations, someone that is implied to be Sariel fills the gaps in the record, which allows him to maintain his stability.
  • Aww, Look! They Really Do Love Each Other: For all the things Shiraori says about Ariel, she really does care for her to the point she is the main reason for saving the Goddess. This eventually comes to a head after the human-demon war, where Shiraori tries to console Ariel over the goddess' betrayal, and admits that she considers Ariel her grandmother and herself "granny's little girl."
    Shiraori: (Narrating) At the beginning, I was doing all this because D forced me to. However, while I traveled together with the Demon King, she let me eat delicious food, and we chatted together. I’m not sure what I should call this emotion that welled up while doing so. I, out of respect for the Demon King’s purpose, want to grant her wish. Her wish to save the Goddess.
  • Badass Army
    • The Ninth Army of the demons consists of dragons disguised as demons. Needless to say, this makes them far more powerful than the other armies.
    • The Tenth Army isn't as powerful as the Ninth, but working together two of the soldiers could probably take down Shun. Shiraori still thinks of them as cannon fodder.
  • Badass Grandpa: Basgas is an elderly man who lived his entire life guiding people through the Labyrinth, thus accruing an impressive set of stats and skills. When his son hesitates to take on Shun's team, Basgas tells him off for being a coward and leads them himself.
  • Batter Up!: Shiraori "borrowed" D's all-destroying single-use-only bat to destroy the elf town barrier and start the war.
  • The Beastmaster: Taming monsters for use in combat is fairly common and it can even extend to humanoid monsters such as goblins. Kumoko was targeted for taming due to her presence disrupting the movement of monsters in the labyrinth. To tame a monster you need to either have it agree to be tamed (unlikely) or beat it into submission. Given that the taming party burned her precious webs and Kumoko herself is stronger than a dragon by that point, neither approach goes terribly well.
  • Bee Afraid: The poisonous horse-sized Finjegoath and its evolved forms in the Elro Labirynth. While individually they aren't much of a threat, they normally move around in groups with a High Finjegoath as their leader, meaning you need to fight about five at once. They're also extremely aggressive and weirdly good at sneak attacks.
  • The Berserker: Activating the Anger, Rage or Wrath skills grants an immense boost in strength but causes a loss of self control. This can be mostly avoided by having Heresy Nullity but seemingly not entirely: Kumoko refuses to use the skill Anger anymore after a single test run.
  • Best Served Cold: Yuugo doesn't have the faintest clue who Shiraori is thanks to her screwing with his head, but even aside from her rage at him threatening Oka-san she carries a serious grudge against him for wanting to kill her when she was just a normal spider. As a result, she doesn't simply kill him when she gets the chance. No, she turns him into a puppet, strings him along for years and has a very gruesome fate in mind for him, though he dies before she can enact it.
  • Better Than Sex. Having your blood sucked feels extremely good and is strongly implied to lead to actual sex soon after. Wrath finds this distasteful, especially when Sophia casually propositions him.
  • Big Brother Instinct
    • Shun vows to become strong so he can be strong enough to protect his half-sister Sue. Their older brother Julius is very fond of both of them and even increases his training so he can remain somebody they look up to rather than being surpassed.
    • Kyouya loved his goblin family and wanted to protect his younger goblin sister. Buirims first making Kyouya kill and then eat her left him in a blind rage.
  • Black Humor: The humor in the story can be rather dark and ranges from jokes about cannibalism to infanticide and how Ariel probably isn't mother (or more accurately grandmother) of the year.
  • Blatant Lies: When D is asking people which side they'll pick in the upcoming conflict she ensures that there will be a conflict by lying about what people are trying to do. Namely, she says that Shiraori intends to sacrifice the people in order to save Sariel. The truth is that yeah, a lot of people will die, but the other viable plan is arguably even more dangerous and trying to interfere could make both plans impossible, killing the planet and everyone on it apart from Shiraori and Gyurie. But she doesn't mention that, instead saying that opposing Shiraori will save humanity.
  • Blessed with Suck
    • It's possible to pick up skills in-universe that are useless because you don't have the necessary stats or support skills to use them properly. For example, Kumoko took the Detection skill early, but the information overload was so intense she couldn't use it until her information processing skills caught up and she gained Heresy Nullity.
    • The Hero and Demon King titles are very powerful, but they ensure an eternal war between humans and demons. Worse, anyone beaten by the Hero gains the title Subjugated By The Hero, which causes the System to spend a non negligible amount of energy to grant the titles. Plus, if the Hero or Demon King attempt to attack a god, the spell would instantly tap into the MA energy as a fuel source to power up their attack. The one attempt not only drained the MA energy gathered by the planet up to that point, but the spell didn't even work right let alone do the job it was supposed to. It simply misfired and killed the Hero, the Demon King and two dozen innocent children because they didn't know enough magic to fire at someone outside the System.
    • After hanging around in the middle layer hunting for awhile, Kumoko accidentally earns the Fear Bringer title by increasing an enemy's fear resistance. This gives her a passive fear aura that cannot be turned off, which causes monsters to run away from her the moment they notice her and decreases her stealth ability. As a result, hunting becomes significantly more difficult since she can't chase enemies into the magma.
  • Bottomless Magazines: The sea urchin-type robot pumps out more bullets than there is room in its body. Shiraori reasons it's using a pocket dimension for this purpose.
  • Body Double: Or soul double in this case. Shiraori was created by grafting a portion of D's soul onto the soul of a spider. When it died, the soul would reach the afterlife and confuse D's subordinates regarding her current location.
  • Brainwashed: The Lust Skill allows the user to brainwash any victim into obeying them, though it comes undone when the user dies. Yuugo used this to control two countries and the Church. It's possible to resist with either high Heresy Resistance (probably) or by being a Ruler as in the case of the Pope, who played along with Yuugo due to Shiraori controlling him.
  • Broke Your Arm Punching Out Cthulhu: Ariel managed to destroy Potimas's most powerful anti-god weapon at the cost of cutting her remaining lifespan to one year and leaving her incapable of combat.
  • Bullying a Dragon: Potimas keeps antagonizing the Gods, even though his first attempt failed spectacularly to the point it caused his world's original apocalypse, unaware he's only lived as long as he did because "D" found it more interesting to tie Gyurie's hands and leave it to humans to kill him. He can't even comprehend what's happening when one of the weakest of the gods, the newly ascended Shiraori, destroys all his armies in a few seconds by herself.
  • But for Me, It Was Tuesday: Sophia genuinely can't remember Felmina at all despite numerous assassination and bullying attempts. She actually feels kind of remorseful and hypocritical in that respect because she knows exactly how it feels to not even register in the eyes of someone you resent with all your being. The reason she can't remember is not just because Felmina was never anything approaching an actual threat to her, but also because what they were 'fighting' over was never important to Sophia to begin with: Waldo might be completely inconsequential to her and no more than a thrall that helps justify her own lifestyle at best, but when Felmina starts knowingly competing with Sophia for Shiraori's attention she starts getting taken much more seriously.
  • The Cake Is a Lie: Immortality is a skill that can be purchased but the points required is staggeringly high - 100 million. "D" explains that she doesn't expect anyone to ever purchase it - the skill exists simply to give the most powerful something to aim for so that their souls will yield more energy when they die.
  • Call a Rabbit a "Smeerp": Shiraori refers to the creatures she makes as her clones, but in reality they're more like little puppet creatures that can be (but usually aren't) granted semi autonomous behavior.
  • Cannot Spit It Out: Shiraori is so shy and anti-social that she is generally incapable of saying more than a few words to other people before just running away, requiring Sophia or Wrath to "translate" for her. In fact, she basically has to activate a fake personality namely a copy of "D" to manage to speak for more than a minute, and goes right back to two to three words per conversation afterwards.
  • Cassandra Truth: Sariel tried to warn the world about the dangers of MA energy, but since she was just a glorified nurse and her warnings were not backed by any kind of meaningful evidence the world simply ignored her. The dragons had a bit more credibility, but everyone hated the dragons for good reason so they were ignored as well.
  • Catch-Phrase: "Nai wa (no way)" for Kumoko and D as well. After not saying it for some years Kumoko even comments on how long it's been since she did so.
  • Celestial Bureaucracy: Unlike the races like dragons and angels who just carve out turf for themselves and fight amongst each other, D and Meido are indicated to have genuinely important responsibilities when it comes to managing the cosmos. Both are implied to be involved in the cycle of reincarnation and the afterlife and D's job actually involves copious amounts of paperwork. Meido apparently sucks at it though because she's so combat focused.
  • Charm Person: Sophia charmed a large number of male students at the academy so she could feed on them more easily. She did it so casually that thinking back on it makes her a little uncomfortable, realizing that someone with human sensibilities couldn't have done that.
  • The Chosen One: At any given time there will be a "Hero" and "Demon King", automatically selected by the System. The Hero leads humans against the Demon King's demons though at the start of the story both sides are avoiding conflict. A Demon King and Hero, Sariel's assistant Foddway and one of Ariel's experimental siblings respectively, naturally arose soon after the System was established; "D" found it amusing and made it part of the System. Shun seems to be an extra special version because Sariel went out of her way to pick him because she knew Shiraori wasn't willing to kill him. As an added bonus, he has a broken 'everything goes the way I want' skill attached.
  • Chuck Cunningham Syndrome: According to the author's notes, originally Shun was going to travel with a young nobleman named Palton and a cranky teacher named Oriza, but this left a gender unbalanced party so both of them simply vanish from the story and are replaced with Katia and Anna respectively.
  • Clone Army: Shiraori has an army of small spider clones scattered across the world and pocket dimensions, carrying out missions, spying, researching magic... and making sure that Sophia doesn't get into much trouble. It doesn't work. For the closest thing she has to a super move, she has them peek out of their pocket dimensions all at once to all cast energy draining Evil Eye of Grudge at once, rapidly deteriorating the strength of her enemy.
  • Cloning Gambit:
    • Potimas puts a piece of his soul into a target and then uses it to take them over, using the new body as a disposable piece to be moved around. When they're overpowered or captured, he has them commit suicide immediately.
    • "D" tries one as a joke by grafting a sliver of her soul onto Kumoko's original soul to transfer the relevant memories of her "death" at the hands of the previous Hero and Demon King. "D" hoped her decoy's presence would confuse the other gods for a few days once it died and its soul ended up in the afterlife, giving her some more time to mess around on Earth. Though she quickly abandons that plan after Kumoko manages to survive and prove to be infinitely more entertaining.
  • Condescending Compassion: Angels are probably defense mechanisms produced by planets themselves to defend against the gods that threaten them and the universe as a whole. Their mission is to protect 'primitive lifeforms,' which indicates how much genuine compassion they normally have.
  • Convection Schmonvection: Averted. The middle layer of the Labyrinth is filled with lava and can be traversed but the heat is enough to cause constant damage. Kumoko has to spend a lot of time acquiring and improving a resistance skill to survive in there. Human adventurers usually avoid the level for this reason.
  • Crapsack World: Most of the world is populated by hostile monsters who can only be confronted in groups and the seas cannot be used for any reason due to the overwhelming number of water dragons. The Humans and Demons are either in a state of open or cold war at all times while the two major religions try to destroy each other despite worshiping the same deity. Worse yet is that the entire skill system is powered by recycling the energy of souls, which will eventually cause the souls to break apart. Constant war and monster hunting is necessary to sustain the world's recovery; peace could doom the entire world. And why is all of that necessary? Because more than half of the planet is dead, shattered rock. The System was repairing that until the previous Hero and Demon King wrecked the energy reserves.
  • Creepy Centipedes: The Elro Ferect are human-sized ones. With a paralytic poison. And they Zerg Rush.
  • Crippling Overspecialization: Meido is the strongest named character in the story, well above even D in power. However, combat is apparently all she's good at, so her subordinates try to keep her busy so she doesn't get in the way.
  • Cryptic Conversation:
    • The Remnants give the B-team a vague warning about what's coming, instead of actually answering Shun's questions. Even Shiraori has no clue what they were talking about, but they're not really capable of answering her questions.
    • Any conversation between Demon Lord Ariel, "Kuro" and "Shiro-Chan", which gives vague details about the overarching plot without actually explaining what it is.
    • Conversations between Kumoko and the Administrators after she hits Taboo Lv 10, as Taboo has given her complete understanding of what the Administrators and the System are for, and thus she has no need to explain them to herself.
  • Curbstomp Battle:
    • Kumoko utterly decimates humans whenever she meets them. She's actually embarrassed when she accidentally destroys an entire fort and everyone inside with a few simple magical attacks.
    • Gyurie delivers a completely one-sided beatdown to Wrath, both to make him regain his sanity and to vent his anger.
    • Happened in the distant past when the dragons decided to exterminate the ancient civilization. All of the civilization's weapons could only barely slow the dragons as entire cities were obliterated.
  • Cyborg: One of Potimas' more powerful avatars is a brain encased in a magically-enhanced mechanical body.
  • Dangerous Forbidden Technique:
    • The Ruler Titles/Skills, all of which warp the soul unless the user has Heresy resistance to match the respective Sin/Virtue.
      • Humility is the worst of the bunch as it allows the user to temporarily fight on par with a god at the cost of their soul being consumed. Ariel wins a hopeless battle with it but has only a year left to live and can never fight again.
    • The Presentation skill directly converts the user's skills into energy and offers them to the Goddess which can be fatal due to the effect on the soul.
    • Parallel Wills basically puts another you inside your body when it's active, which means you can devote your full attention to multiple things at the same time. However, there's a catch: All of them are you, but also distinct, which causes major disassociation problems as time goes on. When exactly Kumoko figured this out is unclear, but she did notice the problem and stop using them this way as much as possible. However, they do still prove useful when moved outside her body to linked souls, such as the Queen Taratect. In this way they can gain pseudo independence while also firmly establishing the original Kumoko personality as dominant. However, she becomes a god not long after and it becomes irrelevant.
    • Heresy Magic directly attacks the target's soul, causing damage and possibly destroying it outright. Even Kumoko during her berserk fit disdains its use. Abyss Magic has a similar overall effect because creatures killed by it have their souls fed back into the System as fuel, preventing reincarnation and effectively being cessation of existence.
    • Corrosion magic is the magic of death itself. It's essentially a save or die attack kept balanced by also generally affecting the wielder as well, especially with the touch radius Corrosion Attack. These attacks are why no spider monster has ever reached Zana Horowa: The two evolutions preceding it both have powerful corrosion attacks that kill them before they can reach that stage. Shiraori, however, is not bound to this limitation and vaporizes Hero Julius with a single glance.
  • David vs. Goliath
    • Any time Kumoko has to fight a dragon. Not only are the dragons much stronger than her, they're also enormous in comparison as she avoided the larger adult forms. However, after Alaba, by the next time she goes up against a dragon she's already an arachne and stronger than a Queen Taratect, meaning she can literally punch three adult dragons to death just to see how her physical abilities have improved.
    • While Shiraori and Gyurie are vaguely allied, she's been making a lot of plans in case he turns hostile towards her for whatever reason. While she's the bottom of the bottom tier and he's lower mid ranked and far more experienced, she thinks she might have about a 20% chance of victory already, but only if he can't counter her trump guard.
  • Deader Than Dead
    • The Heresy element attacks the soul directly, causing it to implode and become incapable of reincarnating. This effect even overrides immortality of the body.
    • Abyss Magic banishes the victim's soul from the System and into the MA realm, where it is absorbed into the world's energy store. This allows it to bypass system protections such as Immortality.
    • Souls can collapse if split into too many parts with skills like Parallel Wills or damaged by Presenting skills; even a being with Immortality will die. The souls native to the world are nearing this point due to the effects of the System.
  • Deadly Gaze: Kumoko has fun learning various eye related powers as a kind of collection, especially since you can activate as many of them as you have eyes. Since she has eight eyes, she can fire up to eight different kinds of magic eyes at once. Some of them rob stamina, health and magic, some cause paralysis, some inflict damage directly and so on. Many years later, Shiraori uses a different kind of eye attack to instantly turn Julius to dust.
  • Deal with the Devil: Discussed. In the backstory, Gyurie knew from the start that seeking out D to save Sariel while still granting her wish of saving their planet was equivalent to offering himself, Sariel and their entire world up to be D's playthings, but still decided to go through with it as he had no alternatives. D also outright admits this when she gets Sariel to agree to become the nexus of the System.
    D: Now then, with my self-introduction out of the way, let us proceed to the negotiation. Dispensing with the small-talk, I shall plainly state my business: Please come play with me.
  • Decapitated Army: Happens frequently during the war when the death of a general, either demon or human, causes their army to collapse in disarray. Justified given they are usually the strongest member of their army, meaning their killer can overwhelm the rest of the army easily.
  • Deconstructor Fleet: While the story starts off as just a twist on the reincarnation genre, as the narrative progresses it begins to show signs of this towards aspects of the genre and other tropes as well.
    • Everything tries to kill Kumoko in the Labyrinth which seems par for the course. Much later she learns they could feel her using Appraisal and perceived it as an attack or a prelude to one. There's no telling how many fights she was in were actually instigated by her gamer's instinct.
    • While Shun is your classic isekai hero, he is absolutely not the protagonist. Kumoko is, and her actions shape the plot such that the author considers her the third most important person in shaping the world into what it is behind only Potimas and D. The story is also subtly critical of his moral positions and the ease with which he gets through things since the world is literally built to make him a born winner.
    • Kumoko herself seems like a classic Gamer Chick hikikomori, the latter of which comes across as mostly an Informed Attribute thanks to the lack of other characters to interact with. Unfortunately, once there are other people to talk to it turns out she's more like an actual hikikomori, social phobias and all. It takes ages for her to actually be able to say more than one or two words at a time and she suffers intense anxiety around most people. She can talk normally to one person, Ariel, but that's kind of cheating given that it's noted that Ariel is basically half her at this point, so it's almost like she's talking to herself.
    • The RPG mechanics incline everyone towards fighting and the spread of monsters has crippled many aspects of civilization. This is on top of skills being unnatural modifications to the soul and XP being derived from an enemy's soul.
    • Oka-chan is apparently a happy Sensei-chan but her chapter reveals she's deeply conflicted about her personality, hobbies, and the resulting lack of credibility. Faced with the inability to protect all of her students she desperately wants support but can't ask due to her position.
    • Telling a villain to Go and Sin No More only works if they acknowledge their shortcomings and want to reform. Otherwise a Cruel Mercy will just make them want revenge.
    • Sophia lives out an otome game, building a reverse harem at a noble academy, but only succeeds at it because she was literally mind controlling the other students. When she's forced to acknowledge what she's doing most of the people interested in her disappear with only two of them explicitly still trying to stay with her.
    • Wrath goes through the monster rebirth genre similar to Kumoko, but is incredibly scarred by the entire affair due to being treated as less than human while also seeing how good and noble the goblins could be.
    • Being an Idiot Hero who doesn't follow the rules and does whatever they want will only kill those around them. Being an All-Loving Hero, trying to save everyone, will let dangerous people escape and/or bring more harm, making the job of those trying to make the world more stable even more difficult.
  • De-Power: The Presentation skill converts all of its users skills and titles into energy which are then "presented" to the Goddess. This is usually a voluntary sacrifice by the faithful but Oka-chan manages to use it to de-power Yuugo. When it is seen from Shiraori's perspective, she says that Oka's soul almost collapsed. It's implied that Presentation was originally developed as a suicide technique for those who could not stand to live in what is basically purgatory, though the world at large has forgotten what the world was like before the System was put in place.
  • Difficult, but Awesome
    • The Appraisal skill is worthless at low levels and only returns information like 'rock' or 'bat' when you try to look at things. It also causes headaches as the ability gets more powerful. As such, it can only really be used either by people with great affinity for the skill or through use of a magic item that lets the user ignore the burden.
    • Detection includes numerous powerful skills within it including the ability to detect magic, nearby enemies and so on. However, the information is so overwhelming it literally functions as an attack on your own soul. As a result it's not just next to unusable, but also makes it impossible to detect things like magic normally. To use Detection, you need to have high level mental skills to handle the information overload, Heresy Resistance/Nullity or both. Once you do, though, the amount of information gained through a quick glance is staggering.
  • Discard and Draw: When Kumoko leaves the System to become a god, she loses her poison abilities, most of her resistances, most of her other magic abilities, Appraisal and several other useful skills that don't exist outside the System. On the other hand, the abilities she keeps, namely her physical abilities, Evil Eyes, thread, dark magic and space magic, are all massively improved. For example, she maybe jokingly maybe seriously indicates that to break her thread through sheer force would require planet buster level attacks. She also gains the ability to create thousands of semi autonomous clones to explore, spy, fight, serve as backup bodies and fulfill preprogrammed instructions like teleporting her to safely immediately if she becomes incapacitated somehow.
  • Does This Remind You of Anything?
    • When Wrath first sees Shiraori drunk the description of her assault on Sophia sounds more like she's being molested than about to be eaten.
    • The way Shiraori asks for favors is a little... open to interpretation:
      Shiraori: I picked up a man. I want to put him up at the mansion.
      Blow: Wh-what the fuck!?
  • Doomed Hometown: Sophia and Wrath both have their hometowns destroyed within years of their birth, leaving them the sole survivors of their families. Especially tragic for Wrath who had come to deeply love his family and the village itself. Sophia, on the other hand, didn't have time to come to view her new parents as really being her parents and is thus not that affected by their deaths.
  • Double Jump: The Space Maneuver skill allows this by temporarily creating footing wherever needed. Technically, the invisible footing can be made to stay in the air for as long as the wielder continues fueling it, but the cost of doing so rises exponentially, which Kumoko uses to gimmick an Arch Taratect to death by teleporting it above a magma lake, forcing it to create a platform to stand on or burn to death. It runs out of stamina and dies.
  • Dramatically Missing the Point: When Wrath hears Dustin explain his utilitarian philosophy, he's shaken by the pope's conviction. He reinterprets his words about not meaninglessly piling up bodies as instead something more like a Sunk Cost Fallacy in that he'll try to aim towards a goal that lets him give meaning to the deaths he's already caused. So he accepts Shiraori's plan to save the world even though it might actually be the worse plan because he needs to have some way to forgive himself at least a little.
  • Drowning My Sorrows: Unable to deal with the stress of what Shiraori is planning for the demon race but still respecting her and knowing she has absolutely no way to stop her, Felmina has to get dead drunk just to get by.
  • Dying Race: The Demons are facing a depressed birthrate which, in addition to their perpetual war with humans and the threat of monsters, puts them in serious danger of dying out. The accumulated damage to their souls from the System means less are able to successfully reincarnate.
  • Eats Babies
    • Shiraori thinks that babies, with their soft, plump features, look delicious. She normally keeps her interest in eating a toddler Sophia in check but her drunken self really wants to test the flavor. Over the course of several years her drunken self escalates from licking to nibbling to biting to actually eating pieces.
    • Mother greeted her newborn hatchlings by skewering and eating them like popcorn. After learning how to spawn Kumoko considered following in Mother's steps before deciding the hatchlings could just bring her some of their prey.
  • Elite Mook: Shiraori's tenth army soldiers are nothing special when seen through her eyes, but each of them has average stats of at least a thousand. She estimates that two of them working together would be enough to give Shun some serious trouble. In the light novel this is actually shown with a sandbagging Sophia, Felmina and a normal mook casually wrecking Shun's party until Feirune comes to save them.
  • Energy Absorption: Shiraori has two natural talents of her own. The first is dimension magic, which is basically teleporting and making new dimensions and stuff. The second is that she can absorb energy very easily seemingly no matter the source which allows her to simply devour a fragment of MA energy straight from the planet and complete her apotheosis. Taking advantage of this, she gets a lot of use out of the ability to drain energy just by looking at things with her Evil Eye ability. This is particularly useful against Potimas' robots, which have special magical barriers. Yeah, she could brute force them but that would be slow, costly and use up an annoying amount of energy. So why not just eat their energy and beat them like that while at the same time buffing herself?
  • Entertainingly Wrong
    • Shiraori is a powerhouse but is avoiding open conflict to conserve energy and fool Potimas; her main display of ability is free use of the rare Transfer magic. Potimas and most Demons assume she is a covert ops specialist with no combat ability, having spent all of her Skill points to acquire Transfer.
    • After observing the battle between Shun and Katia, Shiraori's first conclusion is that she's in a romantic comedy.
    • Balto is wary of Kuro and Shiro because he can tell they aren't normal, but assumes that they must be Rulers. Most people don't even know what Rulers are and this isn't a bad guess given that Shiro held five Ruler titles with Pride, Patience, Sloth, Charity and the new sort of Ruler title of Lord of Wisdom but they are in fact something much worse from his perspective: Both of them are outright gods.
  • Escape Battle Technique: Transfer allows the user to teleport from one location to another; the more skilled the user, the faster and more efficient it is for escaping. However, the Demon King skill blocks transfers within a certain radius of the wielder and particularly skilled users of space magic can interfere with others attempts to teleport near them under at least some circumstances.
  • Evil Cannot Comprehend Good: Shiraori adores Oka-san and works to keep the reincarnators alive seemingly mostly because Oka-san is struggling to keep them safe, but doesn't seem to understand that just because Yuugo probably needs to die doesn't mean that his teacher actually wants him dead, even with all he did to her. She's actually heartbroken about it. So it's probably for the best that Wrath gave him a quick, painless beheading before Shiraori could capture him and turn him over to her expecting that she would want to torture him in revenge.
  • Evolutionary Levels: Monsters can evolve into stronger types of monsters if they fulfill certain requirements (usually reaching a certain level in the current form). The level counter goes back to 1 afterwards. Lower-rank species evolve at 10 but the number goes up for higher-rank species. It's speculated humans could evolve at level 100 but nobody has lived long enough to get there.
  • Expendable Clone: Shiraori's clones are treated as little more than tools, since each one is just an extension of her own will. As such she's more annoyed than anything by Julius being good at killing them.
  • Eye Scream: Yuugo controls three people precious to Shun into shoving needles through their eyes and into their brains while Shun watches.
  • Faking the Dead: During her second encounter with Alaba, Kumoko's nest is destroyed with one attack and she ends up getting covered by rubble. She plays dead until he leaves, though she's not sure whether he actually believed she was dead or was just not worth killing.
  • False Utopia: The country of interstice is a place where nobody fights, there are no hostile monsters, and humans and demons live in harmony. Wrath destroys the country, sending the few survivors fleeing into the rest of the world, but even before that it was really a preserve for souls on the verge of collapse. This didn't actually help the people there at all from their fundamental issues, it mostly just served as a way for Gyurie to feel like he was doing something.
  • Fantastic Racism:
    • Humans and Demons are physically identical and capable of co-existing. Despite this the two races are constantly at war or under uneasy ceasefire while rebuilding. In the backstory, their hatred originated from Demons being humans who used MA energy to evolve. After the ancient civilization's collapse, Humans began to ostracize and ultimately attack the Demons.
      • The Divine Word religion higher ups know what demons actually are, but are noted to be all about ensuring the survival of humanity even though demons basically are just humans. Even in the event that the System goes down, the plan seems to be to wipe out the demons afterward.
      • The Goddess religion also hates the demons, which disappoints those who are familiar with their origins. Sariel does not distinguish between humans and demons, loving both equally, but the religion that worships her thinks it would be a better idea to work with monsters to wipe out demons than the opposite.
    • Goblins are intelligent creatures. They are deeply spiritual and family-oriented, focused more on farming and hunting monsters than anything else. Humans treat them as monsters and wipe out entire villages with little or no provocation.
  • Fate Worse than Death: Just dying isn't really so terrible since the soul will simply reincarnate elsewhere. However, powerful Heresy attacks, dividing up the soul's power and being forced to reincarnate too often over a short period cause damage to the soul and can make it collapse entirely. Shiraori's plan for the world is attempting to limit the reincarnation damage by destroying the System and allowing the souls trapped within to reincarnate normally. However, this requires the immediate price of both killing a lot of people, which isn't a big deal, to causing some short term soul collapse damage among those who have a lot of skills when the System goes down. That one is a major issue because while it's less destructive than the alternative, it's still difficult to accept.
  • Fighting from the Inside:
    • When brainwashed by Yuugo, Katia developed Parallel Will with her female side falling under Yuugo's sway and her male side staying separate. The last act of the male personality was to interfere with the spell on his female side, breaking the brainwashing.
    • Demon Lord Ariel does the same when one of Kumoko's parallel wills tries to absorb her soul. This results in her merging with the fragment, rather than being taken over. She is a lot happier now.
  • Flash Forward: All the side chapters are actually happening considerably later than the events on Kumoko's side of things. As "D" reveals, due to becoming a simple monster, Kumoko was actually able to be reincarnated 6 months before the rest of the class and grew significantly faster.
  • Food as Bribe: The original reason that Shiraori travels with Demon Lord Ariel back to demon territory. For why she stuck with her afterwards, see Aww, Look! They Really Do Love Each Other above.
  • Forced to Watch: Yuugo arranges for Shun's maids and older brother to commit suicide in front of him the instant Shun can see them.
    • Shun knows that Yuugo will do nothing to his sister because he will wait until Shun is there to see him kill her.
    • Shiraori forces Sariel to watch when she sends the Queen Taratect to destroy the First Army and the human fort it is attacking, telling her she only did this because saving the Hero system from deletion consumed energy Shiraori was stockpiling. Wiping out both armies was only necessary to replenish what Sariel wasted.
  • Foreshadowing: When the main protagonist uses appraisal on herself, it says "no name" and she had nearly no Skill Points compared to other students. This is significant because the main protagonist isn't actually part of the class, but rather just a spider inside the classroom. She also notes a strange feeling of familiarity after meeting Gyurie which derives from the fragment of "D"'s soul embedded in Kumoko.
    • Shun and his friends muse that Bald-san's skills are beyond human ability. Wakaba Hiiro who plays Bald-san is Evil God "D" and not above using divine powers in a game.
    • The spell intended to reach the Administrators instead exploded in the classroom and "D"'s use of Japanese and a smartphone indicates she is currently in Japan as Wakaba Hiiro.
    • Shun notes that despite Yuugo being more than deserving of death, he strangely doesn't want to kill him. This confuses him as he's unaware the Kindness skill is distorting his soul.
    • Oka-chan's class list has a blank spot where a student's name should be. Wakaba Hiiro is still alive on Earth so her name is absent.
  • Foreshadowing: Julius and the king discuss a few times how Shun and Sue are probably estranged from the latter because he can't do much for them as a father with his responsibilities, but will eventually understand in time. Shun is more mature than they realize so it seems like needless worrying on their part. However, that only applies to Shun. Sue has grown to be completely apathetic at best to her country and family, both of which have treated her and Shun quite poorly.
  • Forever War: The Demons and Humans are trapped in an unending war, with the closest thing to peace being an uneasy cold war.
    • This situation began shortly after the collapse of the ancient civilization when humans began to persecute demons due to them being humans who evolved using MA energy. The demons consolidated into a nation for self-defense, creating the current situation.
  • Freak Out!: After learning what the Taboo skill is, Kumoko absolutely loses it for awhile and goes from completely happy go lucky to being disgusted with humanity and slaughtering more than a few. It's indicated that this is mostly due to the outside influence of Ariel's hatred seeping through the Kin Domination link and she eventually calms down again. However, she permanently loses the aversion she had to killing humans and her personality becomes somewhat less goofy.
  • From Nobody to Nightmare: Our cute main character was born the lowest of monsters who wanted nothing more than to eat delicious things but within two years had become a man-eating god. Applies doubly when considering her origin as a house spider in Japan.
  • Gambit Pileup: The war between the ancient civilization and dragons ended with a struggle between Gyurie, Dustin, and Potimas over the fate of Sariel. Gyurie came the closest to winning with the backing of "D".
  • Game-Breaker: In-Universe
    • The Sin and Virtue titles carry massive advantages with them, though most of them are also secretly very dangerous as well unless you have maxed Heresy Nullity. Since this stat is hard to acquire, most people can't do much with them without being terribly warped.
    • The Hero skill given to the proper hero has secret advantages built into it. For example, if one hero dies, the next hero gets more out of the title when facing the Demon King. This increases until the Demon King finally loses. This apparently doesn't go in reverse because it's intended as a balancing feature against the Demon King, who is assumed to be stronger by default. Also, in the case that the hero is vastly and hopelessly outclassed by the Demon King, such as a hypothetical fight between Shun and Ariel, then the hero gets proportional buffs to make it a fairer fight. Shiraori considers this cheating. Presumably this one also goes in reverse since the Demon King and Hero must always be capable of defeating each other, but this isn't explicitly stated and is indicated to not really be an issue.
    • The Hero skill has an even more secret advantage built into it, which is it allows the bearer to tap into the MA energy when they attempt to attack a god. This is what depleted the MA energy when the Hero attempted to attack Evil God D. Shiraori notes this is almost certainly an intended function to amuse D.
    • Finally, Shun's personal skill of heavenly protection makes any outcome he wishes for easier. Shiraori considers this one to be particularly unfair, especially since the limits are so vague. Combined with the buffs Shun would get if he met Ariel, Shiraori absolutely refuses to let them meet.
  • Game-Breaking Bug: The skill system is imbalanced due to a secret title, "Subjugated by Hero", received by being defeated by the Hero. Its existence is an unintended drain on the limited energy supply and is helping accelerate the collapse. The title doesn't last long since it's being gained by Julius killing Shiraori's clones, the title going to her since they're a part of her and then being rejected since she can't have titles anymore but it does seem to be a big part of why Shiraori decides to kill Julius. The other reason is that she wants to get rid of the hero title altogether since it's also a huge drain of resources that the System can't afford to waste.
  • Generation Xerox:
    • Ariel, her biological granddaughter Shiraori, and Shiraori's basically adopted daughter Sophia, not by appearance, but by experiences and personality. The three had their childhoods unintentionally screwed up by an Administrator; like to screw with other people (only for it to backfire on them); while talented and powerful they would much prefer to laze/play around but still work hard because they have to; have quite the appetite (for blood in Sophia's case); are morally ambiguous; want to make their mother figure proud (Sophia to Shiraori to Ariel to Sariel); and are kind of an idiot (it's implied Ariel was like this before Sariel's sacrifice). And they can be really petty.
    • As an Arachne, Kumoko looks like a mix of her progenitors: her grandmother Ariel and her other self Wakaba Hiiro AKA her "mother" D. Upon ascending to godhood, because of the bit of her "mother"'s soul she got, Shiraori looks like an exact albino copy of D (except for her eyes, which have 4 red demonic pupils a piece, instead of two horrifying black holes). The two even use this to go partying (against Kumoko's will) as black and white witch twins one Halloween.
  • Gentle Giant: 3rd army commmander Kogou who is constantly mentioned to be a giant and a pacifist.
  • Giant Spider: Taratects range from the size of a pig to larger than whales. Horo Neia seem to cap out at pig sized.
  • Gigantic Adults, Tiny Babies: Newborn Taratects are the size of a pig while Queens are larger than a dragon.
  • Gilded Cage: The settlement of the reincarnated people housed by the Elves isn't exactly gilded as they must manage their own crops and livestock, but it's still a very pleasant place to live compared to the harsher world outside the protective barrier. Despite this the students are painfully aware of how they're at the mercy of the Elves. Potimas wanted to keep their souls free of the System's effects before he began mass-scale experimentation on them.
  • Global Currency: The Aleius coinage is the closest to a global currency as it's minted by the Divine Word Religion, making it accepted in every faithful country. Otherwise each nation has its own coinage which tends to be less valuable the further you are from it.
  • Go and Sin No More
    • Oka-chan tries this on Yuugo, defeating him and then stripping away his power. His response is to dedicate the next few years to getting strong enough to get revenge by destroying everything she's ever cared about.
    • After Yuugo is killed, Shun adamantly claims he should have been left alive to atone for his crimes.
  • Go Mad from the Revelation: When you reach Taboo Level 10, you get to find out the true nature of the Crapsack World, which usually drives most people completely bonkers. Even Kumoko temporarily goes on an Ax-Crazy murder spree after reaching Taboo 10. Some information is excluded and D also modified the skill to constantly bombard the user with feelings of guilt to ensure a breakdown.
  • God Was My Copilot:
    • Evil God "D" turns out to be both the famous online player "Bald-san" from the first chapter of the side story, and the real Wakaba Hiiro the other reincarnators went to school with.
    • Ariel's generals "Kuro" and "Shiro" are revealed to be the gods Gyuriedistodiez and Shiraori, though almost no one they interact with even know this.
    • Late in the story it's revealed that Shun's companion Hyrinth is in fact a clone of the Gyuriedistodiez.
  • Godzilla Threshold: The imminent collapse of the System due to souls wearing out leads to Shiraori's plan to cause a massive war as the energy freed in the deaths of people can be used to prevent a disaster.
  • Good Thing You Can Heal
    • Kumoko would have died several times if it weren't for [n%I=W] restoring her damaged body. This includes replacing lost limbs and eyes, restoring petrified flesh, and healing a gaping abdominal wound.
    • As part of her first battle Sophia gets her head cut off, only for her body to catch and reattach it in one move. While her head was still severed she was losing HP at a phenomenal rate but hadn't quite hit 0 by the time it was reattached.
    • Wrath at one point has a hole blasted through his head. Only killing a knight and leveling up to restore his body saved him from death.
  • Grand Theft Me: Kumoko attempts this on the Queen Taratects and Demon King Ariel, but only succeeded with two Queens. The Demon Queen's soul was able to resist Kumoko's fragment enough that they instead merged, which resulted in Ariel taking on some of Kumoko's traits. Admittedly she is a lot happier now.
  • Guide Dang It!: Kumoko's feeling about the skill system for quite a while as she has no idea how systems like magic work and has to figure out available skills by randomly guessing names.
  • Had To Be Sharp
    • Ariel is the oldest and most powerful Divine Beast not because she was the strongest or smartest but because she managed to survive where her comrades died from, if nothing else, old age.
    • Kumoko herself starts as the weakest monster in the Elro Labyrinth without even full understanding of her abilities, but when forced to fight every day just to survive and keep herself fed she gets much stronger within a very short period of time. Within no more than a few months she becomes one of the most dangerous beings in the labyrinth with only the earth dragon and Mother being absolutely beyond her ability to take down. The likes of Shun, by contrast, had to start as infants and even with seemingly genius level abilities had little chance to get any meaningful training done, taking years to accomplish what Kumoko had to handle within weeks.
  • Half-Human Hybrid
    • Half-elves exist but are banished from the Elf Village after becoming adults. Anna's experience was apparently traumatic. After Shiraori, Ariel and Dustin's genocide, the only pure blooded elf left is Oka-san.
    • The country of interstice was home to a mixed population of Demons and Humans who had intermarried to the degree that pure-blooded members of either race were hard to find. It was very peaceful, but destroyed by Wrath due to him having gone berserk.
  • Hammerspace: Spatial Magic allows for the creation of a pocket dimension to store items. Kumoko mainly uses it as a larder for excess food while Wrath stores his extra weapons in one.
  • Henchmen Race: The Taratects were created by Ariel for the sole purpose of acting as her personal army; the Queens are little more than machines set to produce offspring which are in turn programmed to fight and become powerful. This proves to be a major vulnerability that Kumoko ends up exploiting. All the spiders are linked with the mother dominating their offsprings wills, which forms a connection that allows the passage of will/soul. Since the Queen Taratects have almost no will of their own, Kumoko's parallel will fragments find it rather easy to invade their minds and devour them from within, which serves as a staging ground to attack their mother, Ariel. Ariel is more resistant to this kind of tactic but still has no way to defend against it.
  • Heroic BSoD: Learning that Potimas lied about why he wanted the students was the last straw for Oka-chan.
  • Heroic Sacrifice: Sariel willingly agreed to be killed and converted into MA energy to save the world. She actually had to be restrained by her friends and followers because she was so willing to do so.
  • Hidden Elf Village: The Elves live in a secluded forest village protected by a near-impenetrable magical barrier. This is needed as the Administrators and Divine Word Religion would both happily wipe them out if possible.
  • Hoist by His Own Petard
  • Hope Spot: After Kumoko kills most of the subjugation team she lets the others go but tags them so she can locate the Labyrinth's exit. The survivors reach the surface only for her to teleport in and kill them.
  • Horrifying the Horror: Wrath and Sophia consider Shiraori to be effectively invincible, so they're shocked to realize that there's someone out there that she doesn't even want to think about challenging.
  • Humans Are Bastards: The story presents humans as being willfully ignorant, almost universally selfish and while they do admire the true heroes like Shun and Sariel, they have no desire to emulate them. They're happy to just take advantage of their kindness and then turn on them when their own well-being is at stake. As a result, Shiraori tends to find them slightly distasteful by default when viewed as a whole.
  • Ignored Expert: The Dragons warned the ancient civilization about the dangers of using MA energy and were uncharacteristically forthcoming about exactly what would happen. However, MA energy was just so valuable and the dragons so (rightfully) hated that they were ignored.
  • Ignored Epiphany: Occasionally Kumoko's musings turn toward her own shortcomings and how she's not all that different from the monsters she is slaughtering. She then immediately dismisses such thoughts from mind and continues to behave in the same manner.
  • I Let You Win: In the light novel, Sophia is openly with Yuugo's group at the time Shun is trying to flee. Even though she is clearly not fighting at all seriously, she still barely manages to find a way for them to escape from her plausibly without actually seriously injuring any of them.
  • Immortal Immaturity: Most of the reincarnators do not really act the age that they should mentally be, which would be their early to mid 30s. The author's defense (via D) is that many of them have had no opportunity to learn or mature because they've been locked away from the world in a hidden elf village that didn't want them to grow at all as people.
  • Immortal Procreation Cause: Demons and elves have much lifespans several times that of humans, so they "naturally" have far lower birth rates and correspondingly lower populations. This is causing them immense social problems due to the dying world cutting their birthrate even further. The humans are having the same problem, but with their greater fertility it's not showing yet.
  • In Vino Veritas
    • When Kumoko won't stop killing humans Gyurie gives up on that and just goes drinking with her to get to know her better and explain himself a little. We don't actually see the conversation for a long time but eventually we do see a chunk where he admits that he really can't argue with her calling him a loser, something she'd presumably said earlier in the conversation. Normally she keeps her mouth shut and her guard up around him, but when she drinks she babbles nonstop.
    • Shiraori is usually completely silent and withdrawn but when drunk she'll start childishly babbling about how to train, bemoan her rough childhood, and eat parts of Sophia's body.
  • Irony:
    • Kumoko believes she was the least popular girl in class due to her anti-social nature, while pretty much all the reincarnated boys actually thought Wakaba was the hottest girl in class, considering her a mysterious "cool beauty." This may also be Kumoko's house spider memories mixing in, as no one other than Oka liked it.
    • One of the experiments Potimas discarded as a "failure" turned out to have an immortal body after all. If Potimas had had enough human decency to research how to neutralize his own daughter Ariel's poison blood, he could have had his immortality before even resorting to the extreme methods that destroyed the world. Potimas himself ruminates on how unfortunate this is right before she comes to kill him centuries later.
    • Dustin's efforts to save humanity by opposing Shiraori's plan are actually going to result in more human deaths / soul collapses than if she succeeds, as her plan will only cause the death of those with lots of skills, not the majority of humans, while letting the status quo go on will result in everyone suffering soul collapse from being processed too many times by the System. Worse, Dustin's attempts to recruit Shun to combat Shiraori could kill everyone instantly, as Shun fighting Shiraori would burn energy being used to sustain and rebuild the planet. Everyone except Shiraori that is, as she can just teleport away.
  • It Can Think: To Kumoko's surprise, Queen Taratects are highly intelligent and can even understand speech as she learns after eating Mother's soul. They just have very weak wills because they're just a puppet race for someone much more powerful.
  • "It" Is Dehumanizing: Gyurie refers to Shiraori as "that" rather than her name or even gender. However, while it is in part a kind of distancing term, it's also a sign of how he's nearly in awe of her.
  • I Will Punish Your Friends For Your Failure: Shiraori makes Sue flip by promising to leave her brother Shun alone. However, it's actually a kind of empty promise not because Shiraori hurts him anyway but because she had never planned to hurt him to begin with. So after Sue cuts ties, Shiraori admits to herself it was kind of an unfair deal and personally adds Sue to the list of people that will be sheltered when the System goes down.
  • Jerkass Has a Point: Blow is disrespectful to Ariel and berates Shiraori for lazing around eating their food, despite them working to save the world. The reason for this is that Ariel is destroying the peace his brother fought so hard to maintain while Shiraori is gorging herself when the demons have just barely gotten food production above starvation level. Acknowledging this, she grudgingly forces herself to give a partial explanation and begins handing over some of the material from her clone's worldwide intelligence ring.
  • Jerkass Gods
    • Oka-chan explains that the Elves are fighting against the System because the Administrators are using it to amuse themselves and feed off people's energy. Of course Potimas knows it's being used to restore the nearly dead planet, he just uses this lie to get people on his side.
    • Even D seems to have rather major distaste for some of the other divine factions. She consider dragons arrogant thugs while angels are basically stupid robots from her perspective. The latter are seemingly just treated with contempt, but she has major dislike for the former and always takes potshots at them.
  • Jumping the Gender Barrier: Katia slowly developed feelings for Shun but suppressed them as she still identified as a man in her mind. After breaking free from Yuugo's mind control she begins identifying as a woman and starts some low-key flirting with Shun. Shiraori comments that "D" reincarnated him as a woman in first place because she was aware in his previous life he was trying to force himself to have a crush on Wakaba to convince himself that he wasn't in love with Shun.
  • Just Think of the Potential: Potimas discovered a seemingly endless supply of energy that could be used to power entire nations and even evolve the human form. Nations greedily began exploiting this energy despite warnings, triggering an apocalyptic war with the dragons.
  • Kaiju: Queen Taratects are enormous and incredibly powerful. A single one wiped out a heavily defended fort and the army attacking it.
  • Kick the Dog: While it's later shown that Shiraori was controlling Yuugo during his attempt at revenge, the story still makes an aside to show him doing really shitty things outside of Shiraori's instructions, causing her to have to cover up for him. That way she can be kinda morally shady without making him either terribly sympathetic or having her be responsible for the actual deaths he causes.
  • Killer Rabbit: Shiraori's 3 palm-sized hatchling spiders that were summoned to guard Sophia.
    Shiraori: Although they are not strong individually, if there are three of them, they can at least repel the Dragon class.
  • Kill the God:
    • Attempted on "D" by the previous Demon King and Hero at the urging of Potimas, or so it seemed. The attack was actually intended for Gyurie but was redirected by Sariel. As "D" existed outside the system and is effectively one of the Powers That Be, the attack failed.
    • Potimas has been constantly refining his robots and cyborgs in preparation for killing Gyurie.
    • Angels are a race of gods whose entire purpose in existence is killing every other god they encounter.
    • A god went on a rampage at one point millennia ago, slaughtering a large portion of the Angel race and quite a few other gods to increase their strength and skills in battle. The Maid really wishes "D" would stop bringing up her embarrassing past.
  • The Lady's Favor: Goblins give pressed flowers to hunters leaving the village with the hope the hunter will return with the flower alive. This tradition is based on the flower Ariel gave to Gob-Gob, the first goblin, which he never had a chance to return.
  • Land Mine Goes "Click!": Wrath buries easily broken explosive swords in a field. When somebody steps on the surface, the sword beneath shatters and explodes. This proves less than effective against magic once the trick is known: A single wind spell detonates the entire minefield.
  • Laser-Guided Karma:
    • Yuugo suffers near immediate reprisal whenever he raises his hand against Shun. Even if by the end he was being pushed to insanity by Shiraori.
    • Played for Laughs with Sophia unconsciously badmouthed her master and was immediately punished by Drunk!Shiraori.
  • The Last Dance: Ariel is going to die soon due to the System distorting her soul. She decided to spend her last days doing what she had always wanted: Fighting to save Sariel.
  • Last Fertile Region: Shiraori reveals that the two continents and surrounding oceans are actually the only livable portion of a mostly-dead planet. The purpose of the system was to accumulate enough energy to restore it.
  • Lethal Lava Land: The middle layer of the Elro Labyrinth is mostly lava with paths of solid ground or sometimes just islets. The heat alone is hazardous, not to mention falling into the lava or the fire drakes that live in said lava.
  • Let's You and Him Fight: Invoked multiple times.
    • Shiraori deliberately manipulated Wrath and Sophia so they would encounter each other and fight even though they both ended up joining Shiraori's camp after talking for a few minutes.
    • Shiraori doesn't bother explaining her plans to the majority of the cast because she knows "D" will think without conflict things are too boring and trick everyone into fighting anyway. Which, of course, "D" does.
      System: A World Quest is issued: Will you obstruct or will you support the plan of the Evil God who is scheming to sacrifice humanity in order to avert the destruction of the world?
  • Level Up Fill Up: The special skill [n%I=W] allows this for reincarnated individuals, completely restoring their bodies in the process. For Kumoko this was a vital skill until she learned healing Skills as it allowed her to recover from injuries that would otherwise have been disabling or fatal. At higher levels it doesn't completely fill the HP due to the soul energy it consumes being finite.
  • Lies to Children: When Shiraori is making an analogy for why Gyurie's teleportation being interfered with injured him she uses the example of leaping through a doorway. However, before you go through it, someone closes the door and locks it, causing you to crash into it headfirst and hurt yourself. She admits that this is actually nothing like that but it makes intuitive sense, so just think that it works like that if you want.
  • Life Stream: Every planet has a well of spiritual energy, comparable to that of gods but lacking a conscious will to direct it. If expended the world will die, along with any creature that lives on its surface. Potimas dubbed this "MA energy" and the ancient civilization, unaware of its true nature, abused it until the dragons stole what remained. The System is attempting to restore the MA energy but is on the verge of collapse.
  • Lighter and Softer: The light novel, which is rated 13+, cuts down on some of the web novel's darker elements. Kumoko is more willing to help people, only resorts to cannibalism to avoid starvation and the first time she kills someone it's an accident, though she makes it clear that she has no real moral compunctions against doing so. Yuugo only proclaims a desire to destroy everything Oka-chan holds dear, not flat out rape her. Katia is also never shown recognizing the need to abandon her parents, so they make it out fine.
  • Living Relic: Potimas, Ariel, and Dustin are the only mortals left who remember the world before the System was created. Potimas has survived via Magitek; Ariel through her unique body; and Dustin through repeated reincarnation with the Temperance skill.
  • Loose Canon: The "Teach Us, D-sensei!" side chapters have the gods D and Meido explaining various elements of the actual backstory of the novel with the exact same dynamics they show in the main story. However, the one they're explaining things to is the reader, so these Breaking the Fourth Wall chapters can't exactly be said to be occurring within the story itself, even if all the info and character traits in them are consistent with the main work.
  • Loose Lips: Kusama leaves top secret documents lying around his personal quarters and blithely reveals inside knowledge to Wrath during conversation. Even Wrath, who's on the opposing side of the war, worries Kusama's too inept.
    Pope Dustin: Our ninja is so rubbish that it’s dangerous.
  • Losing Your Head
    • Wrath cuts off Sophia's head during their first encounter. Her body catches it mid-air and reattaches it.
    • The third "Teach Us, D-sensei!" omake starts off with the Maid beheading "D". "D" is casual about the affair and gives the entire segment in this state, so the Maid follows up by reducing her body to mincemeat.
  • Lost Technology: Though mostly destroyed by the Administrators, some of the ancient civilization's creations survived to the modern day, though only Potimas actually controls it.
  • Love Chart: The author refer to it as "Shiro’s personal “heart” power ratings". This is specifically noted to be the character's opinion, though, and therefore falls apart somewhat on closer examination, because she isn't very good at reading people.
    Author Note (Chapter 276): Demon King > sensei > the Goddess = the pope > oni-kun >>>> The unsurpassable wall >>> vampire girl > loser (Kuro)
  • Love Triangle: Between Sophia, Waldo and Felmina. Sophia doesn't even notice.
  • Magical Eye: The Evil Eye skills give a variety of status and damage effects to whatever the eye focuses on, one per each eye. Kumoko dreams of having a different one for each of her eight eyes. Demon Eyes are a weaker version. They remain one of her strongest trump cards as a god, especially the Evil Eyes of Gluttony.
  • Magikarp Power
    • All skills start off pretty mild and barely have any noticeable effects. Level them up enough and things start to escalate exponentially. Case in point, the "Appraisal" skill starts giving nothing more than a general name such as "Wall" or "Deer" but at higher levels reveals every stat and in-depth details.
    • Taratects, Kumoko's species, are one of the weakest monsters there is. However, by picking to not grow to adulthood for as long as possible they start to eventually unlock very possible classes like Zoa Ere with the complete chain ending up at an Arachne, a humanoid spider monster. They can also end up being Arch Teratects or even Queen Teratects as well. The latter is even stronger than dragons.
  • Magitek: The ancient civilization was comparable to modern day Earth until it discovered MA energy and incorporated it into their technology. Potimas took this even further, developing all manners of futuristic machinery using that power and protected by anti-magic barriers.
  • Manchurian Agent: Potimas embeds fragments of his soul into people so he can control them, both indirectly and directly. He had compromised most of the government of one country and even placed a fragment in his daughter, Oka-chan.
  • Man-Eating Plant: Some monsters grow like plants, only becoming mobile and hostile past a certain age. Goblin villages on Magic Mountain cultivated these monsters, making sure to harvest them just short of maturity.
  • Mark of the Beast: Skills such as Heresy Magic and Titles such as Blood Relative Eater, are obvious signs of evil actions. Of particular note, the Divine Word Religion has a policy of locating and killing any person who acquires the Heresy Magic or Taboo skills as they are considered sinful and dangerous. Heresy Magic is actually banned because at max level it grants a level of Taboo and when Taboo is maxed, the person with the skill learns the truth of the world and goes crazy.
  • Meatgrinder Surgery: Treatment Magic is generally only limited to healing injuries, not curing diseases. So when Kumoko decides to treat a woman and child suffering from organ failure, she has to sedate them and then tear out their failing innards and regrow healthy ones while they're unconscious in order to save their lives. She remarks that it's a rather barbaric method that would make any proper doctor faint.
  • Medieval Stasis: The world has been stuck in its current feudal state for centuries at a minimum. It's enforced by the System, which prevents chemical reactions such as gunpowder burning; this ensures people fight the old-fashioned way.
  • Metaphorically True:
    • The Taboo skill gives information on the world before the System was put in place and places the blame for all the bad things that happened on humanity. However, it generally leaves out the involvement of the Dragons, who stole centuries worth of MA energy. Potimas, who developed in the first place and hid the dangerous side effects till most of the world was addicted to it. and Sariel and Gyurie, who had the power to destroy all the MA Energy facilities but did nothing instead out of fear of "harming" humanity.
    • The system issues a quest claiming Kumoko is the "Evil God who is scheming to sacrifice humanity in order to avert the destruction of the world" Only the parts of humanity with high levels in the System will actually have to die, and trying to stop her is very likely to speed up the destruction of the world and all of humanity dying.
  • Mind Rape
    • Heresy magic directly attacks the mind and soul, capable of implanting straight-up insanity into a target. Using Detection or Appraisal without proper secondary skills is a self-inflicted version.
    • Kumoko unintentionally inflicts this on Ariel during her attempted takeover. She survives the ordeal but as a result of merging with Kumoko's soul fragment her mind is permanently changed. Kumoko and Gyurie find the new personality pathetic, though the changes are actually more superficial than they originally seemed.
    • Level 10 Taboo not only reveals the origin of the System, it also bombards the mind with feelings of guilt. Combined, even mild-mannered people will go insane. It's significantly less effective on people who weren't born inside the System: Kumoko goes briefly berserk and the manga indicates it keeps her from sleeping properly, Shun collapses but stays rational due to getting a more complete picture of the situation while Wrath was already rampaging thanks to, well, Wrath.
  • Mistaken Identity: When Kumoko finally leaves the labyrinth, before too long she ends up saving a young noblewoman who believes her to be a messenger of the goddess and a Divine Beast, one of whom is known to be a spider. Namely, she's mistaken for her grandmother Ariel, though her name isn't given for some time after this. Ariel is not technically a spider and certainly doesn't look like one, but reliable information about her is apparently scarce since she keeps to herself.
  • Mobile-Suit Human: Puppet Taratects are human-sized mannequins controlled by the threads of a single palm-sized Taratect in their chest. Ariel's original models were obviously puppets but Shiraori helped her refine them to the point they can almost pass as an actual human. Among their species only Queen Taratects are stronger.
  • Monster Is a Mommy: When Yuugo attempted to kill Shun, he brought along a powerful earth drake to back him up. It was strangely docile, which puzzles Shiraori. In the web novel this is never explained and it's never mentioned again, but in the light novel it turns out to have been the parent of Feirune: It came along with Yuugo's summoner because it needed to find its lost egg, then went on a rampage once it got where it needed to go. Unfortunately, Feirune and Shun kill it before realizing what it is, but Feirune is only temporarily depressed since she had no way of knowing and never grew up with it anyway.
  • Monstrous Cannibalism: Kumoko finds that her siblings are eating one another after she hatches and that Mother is eating the new-born taratects as well. She later kills and eats one of her siblings, in self-defense and to not be wasteful. In the manga it was already dead, having been killed by an adventurer. This earns the "Kin Eater" title, awarding her the Heresy Magic and Taboo skills, both of which are considered sinful by the Church.
  • Morality Kitchen Sink: The full range of morality is there but characters who really adhere to one extreme or the other and act on their beliefs are surprisingly rare: Potimas and Natsume are evil, Sariel and Shun are good. However, the viewpoint character is extremely gray when it comes to morality and finds both extremes distasteful: Potimas and Natsume are obviously assholes and major threats to every decent person on the planet, but Sariel and Shun's fixation on Doing The Right Thing is portrayed as naive, shortsighted and even outright dangerous: Sariel is one of the people most responsible for how shitty the world is while Shun's kind nature is something not even his closest allies agree with and, if events continue in typical isekai LN fashion, will put the world in immense danger, possibly destroy it and even if flawlessly successful will cause far more damage in the long run.
  • Morality Pet: There's no reason that Shiraori has to keep the reincarnators safe, it's just something she chooses to do. She also took in Sophia and Wrath with no thought as the potential benefits and ensured their mental and physical safety as best she could even though she didn't know either one and owed neither anything. She has a particular soft spot for Oka-chan, though in that case it's mostly gratitude. Finally, Ariel is kind of a subversion. Her love for her grandmother is kind of sweet but her attempts to make her happy and give her life meaning are morally ambiguous at best.
  • Mordor: Averted with the Demons' nation, much to Sophia's disappointment. It's actually hard to tell you've crossed a border between Human and Demon land since they're physically identical to humans, grow the same foods, organize their society the same way and have the same type of architecture.
  • More Predators Than Prey: Kumoko notices that every creature in the lower level is a predator and wonders how the population can sustain itself. She eventually determines the likely reason is a number of small snail-like creatures. They taste horrible and inflict the damage of death itself on eaters so she reasons they're desperation food for the weaker monsters.
  • More Than Mind Control: Shiroari puts clones of herself into Yuugo's brain so she can control him at will, but only directs his hatred towards specific targets rather than truly control him. He often surprises her by being more aggressive about it than she expected.
  • Morton's Fork: There are two possible ways the planet can finish being repaired. Both of them are terrible.
    • First, the world continues warring until enough power has been drained from souls to fix everything. Before the world can reach this point, Sariel's soul will have collapsed from being too drained and then Gyurie will take her place and meet the same fate, only faster. Making it worse is that the Divine Word Religion is needed to keep things stable after Sariel dies, but Dustin is disbanding it to support Shun. Shiraori estimates that at least one quarter of the population's souls will die just from soul abrasion before that point is even reached, causing them to collapse like their gods'. This option is also risky in that things could get a lot worse, up to and including the death of the planet and everyone on it should anything go wrong. Shiraori rejects this plan as being the more risky of the two, but is privately mostly motivated by the desire to fulfill her dying grandmother's last wish.
    • Second, the System is forcibly shut down ahead of schedule and the energy used to power it instead going to fix the planet. This reduces the risk of soul collapse caused from soul abrasion, saves Gyurie and allows Sariel to simply die rather than have a Fate Worse than Death. Shiraori estimates that roughly half the population will probably die this way when taking into account the collapse of the civilization that depends on the System and the people whose souls will collapse immediately from having their skills stripped. This sounds worse on paper, but she's also making efforts to have as many people with lots of skills die beforehand as possible, which will keep their souls safe. So between the two, it's a bit of a wash as to which one is worse.
  • Mundane Utility
    • Kumoko's spider silk is a powerful defensive and offensive weapon which she can also use to go fishing. She just wishes the drakes and dragons she catches would have a little more dignity.
    • Shiraori has millions of clones scattered around the world, training and carrying out missions for her. She can also use them to metabolize alcohol out of her system and help her talk with people.
  • My Skull Runneth Over: Higher-level sensory powers like Detection or Appraisal can actually harm the user if they're not ready for the mental load. Detection is so overwhelming it actually counts as an attack on the user's soul. This is why most of the world uses Appraisal gems instead.
  • Necessarily Evil: Goblins are considered just another kind of monster because they're very aggressive towards anyone that isn't part of their village. However, this can't really be helped: They only live to about the age of eleven or so unless they manage to evolve twice. Since you can only level by killing monsters or people, they have to constantly fight and kill just to reach the age where other humanoids are hitting puberty. Their short lives also keep them from developing more complex society because you can't have any kind of professional in a society with the massive turnover rate they have.
  • The Needs of the Many: The reason the Divine Word Religion started a war with the Goddess Religion was because the Pope believed weakening them would save more lives in the long run once the Goddess died and her existence became common knowledge.
  • Neglectful Precursors: The ancient civilization that produced the robots nearly destroyed the world by exploiting the MA energy, triggering a war with the dragons that left most of the world uninhabitable. Some of their creations remain, hidden and buried, which continue to cause damage.
  • Nice Job Breaking It, Hero!:
    • The previous Hero and Demon King's failed spell was intended to kill "D" and free the world from the System... despite D being one of the unkillable Powers That Be and the System being in place to heal the world that mortals destroyed. Instead, it just killed a classroom of innocents and depleted the MA energy critical to the restoration.
    • "D" instructed Gyurie not to kill anyone in the System, ostensibly to avoid disrupting it but in reality just to make things more interesting. Thanks to this and "D" losing interest, Potimas was able to run amok and indirectly was responsible for what MA energy had been gathered being lost when the Hero and Demon King tried to kill "D".
  • Ninja Pirate Zombie Robot: Ael, a maid Puppet Taratekt co-created by Shiraori and Ariel to bodyguard and spy on the higher command of the Goddess Religion. Her species are actually palm sized spiders that control a marionette outer shell, and are actually just slightly below Queen Taratekts in terms of stats.
  • No Accounting for Taste: Balto has no clue what his little brother sees in Shiraori. The answer is... well, she's scary, but Blow doesn't realize he fears her and mistakes his tension for attraction.
  • Non-Action Guy: Half of the Demon Army thinks that Shiraori's Tenth Army is only good for spying and assassination due to their white outfits and Shiraori's tendency to run away from Blow. They are actually the second strongest army, right behind the Ninth Army which is full of humanoid dragons. Potimas makes the same assumption about Shiraori due to this.
  • No Party Like a Donner Party: In the light novel, Kumoko only eats her spider sibling when she's not sure she can survive until morning unless she eats something.
  • No-Sell
    • By leveling resistances you can eventually gain immunity to the element you're being attacked by. Heresy Nullity is particularly valuable not because heresy attacks are common - they're banned by the dominant religion - but because unless your soul is immune to outside influences then the Ruler skills will burn through your soul and radically warp your personality.
    • Pain Nullity is in fact No Sold itself by a magic spell that creates the illusion of pain inside the mind of the target. Alaba is so unused to pain after so long with Pain Nullity that it causes him to flinch at a critical point.
  • Nothing Personal: It's not much consolation to Shun, but Shiori killing his brother Julius was simply because she needed to take down the Hero system. She actually had some level of respect for him and gave him a quick, clean death as a result.
  • Not the Intended Use: D is rather pleased to see Kumoko using Parallel Will soul fragments to travel along mental connections and devour others souls. The ability was not designed to do this and figuring out a trick like this is an indication that she has aptitude for godhood.
  • Not Quite the Right Thing: Shun's friends notice that Yuugo is fixated on him, so they do their best to keep the two separated. In truth, what Yuugo needed was a simple wake up call. As his profile puts it, he was actually calling for help but couldn't admit it and the signals he gives off are hard to read. If Shun and his friends had tried to get him to open up he might have become a valuable ally instead of an enemy since he's not a fundamentally terrible person.
  • Not So Different: After reflecting on her treatment of Felmina, Sophia starts to think that Felmina must feel the same way that she did when Wakaba Hiiro (allegedly) ignored her existence.Only for her to get mad at Shiraori (who she thinks is Wakaba) for treating Felmina better than her.
  • Oblivious to Love: Sophia noted her mother was an airhead who completely missed that her childhood friend and servant Merazofis was in love with her. Sophia's father noticed but knew it would never go any further.
  • Official Couple: While Shun has numerous wannabe suitors, the one the story generally pushes as the main girl is Katia, though currently Shun is trying not to notice that she's a girl at all. It's still quite up in the air, however, and is a very small subplot to begin with. One that isn't even about characters who could be considered the main cast at that.
  • Off the Chart: In the manga Kumoko makes a mental chart comparing her size to that of a human and Mother. Mother is represented by a giant claw with the leg going out of the panel.
  • Oh, Crap!: The Elro subjugation team's reaction when they saw a partially eaten Arch Taratect (a ridiculously powerful S-ranked monster) corpse, a sign that something is actually strong enough to prey on it.
    • Kumoko did this a lot until she finally evolved into an Administrator, usually accompanied by a shout of "Nai wa!"
    • Sophia's reaction whenever Shiraori gets drunk.
    • Shiraori is not prepared to learn that the sea urchin type-robot she just killed with significant effort isn't the "final boss" of Potimas's robot army - it's the production model version. It's not enough to pose a serious threat to her, but it does force her to use her anti Gyurie trump card in front of Gyurie himself. Fortunately, he doesn't have the time to work out a countermeasure before the two begin their own fight.
  • Once More, with Clarity!
    • Pops up periodically when two characters are involved in the same event but are either opposing or unaware of one another. Examples include Shiraori intervening after Oka-chan depowers Yuugo and showing both sides of the battle between Wrath and Sophia.
    • Several cryptic conversations among the demons surrounding the Human-Demon war are revisited much later. Not only do they have context that was originally missing, but the conversations are also told from the perspective of somebody who knows what's actually happening.
  • One Steve Limit: Averted with two skills: Hero and Demon Lord. There exists a version of each that can be earned or purchased via the usual skill system and the unique version that the System automatically gives to a single person. The former is merely a stat boost while the latter is a stat boost and marks them as the leader of humanity/demons. It's indicated that having the Hero or Demon Lord skills make you more likely to be picked the next time the spot becomes vacant, however.
  • Organic Technology: Queen Taratects are actually highly intelligent, but they have almost no will of their own. Kumoko compares them to giant walking computers that only fill out a handful of preprogrammed instructions. She seems to find the idea intriguing and useful. Not only she she exploit the link between her and Mother to devour the weak minded creature, but also creates more Horo Neia to serve as backup bodies and later small clone offshoots of herself with similar instructions.
  • Otome Game: Sophia is unaware of it, but her time at the noble's academy hits all of the cliches as she obliviously builds a reverse harem and garners the hatred of a scorned fiancee whose social standing is destroyed as a result.
  • Our Angels Are Different: Angels are a race of gods whose entire purpose is exterminating other gods and protecting "primitive" species such as humanity. They evolve by taking power from the gods they kill; they apparently gained a humanoid form after killing the god who created humans. They're usually emotionless and behave more like machines than living beings. Sariel is a "stray" Angel who was left alone after the Maid destroyed most of her race. She gradually developed primitive emotions and opinions but retained her desire to protect weaker species. Strictly speaking, this was not a good thing as it led her to doing some seriously stupid things out of good intentions.
  • Our Demons Are Different: Demons are physically indistinguishable from humans and their culture is very similar as well. However their physical parameters are much higher than a comparable human and some inherit demonic abilities. The similarities are due to demons being the descendants of humans who "evolved" using MA energy. Overall their race is less numerous, which causes them to feel the effects of the overall lowered birthrate far more strongly than the humans do.
  • Our Dragons Are Different
    • True dragons are gods, or at least become them when they reach adulthood. They're dicks. They can also assume human form, though if Gyurie is anything to go by they don't actually look quite human: He's solid black from head to toe with only his red eyes looking different. Additionally, the armor he always seems to be wearing is implied to be his skin.
    • Mature dragons vary in appearance both between and within their own species. Earth Dragon Alaba looks like a giant scaled dog thing while Fire Dragon Rendo is a traditional winged dragon. Like true dragons, they can assume human form. However, it's not clear if this is a natural ability of theirs or if Gyurie is rigging the System.
    • Dragons are the evolved form of drakes, which in turn can evolve from other low-level species. Only high-tier drakes look like dragons, while lower-tier drakes range in appearance from dinosaur-like Earth Drakes to fish-like Fire and Water Drakes. Kumoko is baffled at how of the fire drakes two look like seahorses and catfish; the eel-like drake at least has an Asian-style dragon body.
      • Most of these dragons are descendants of Potimas's experiments in merging dragon DNA with other animals.
  • Our Elves Are Better: Of the Wood Elf variety, they are a neutral nation that lives in a magically defended village. They have extremely long lifespans and generally view other races as needing guidance. Potimas created their race during his research into immortality by forcibly evolving humans. Every elf is either brainwashed to serve him or is a clone containing a copy of his mind; he maintains genetic diversity by abducting humans and evolving them into elves for breeding stock.
  • Our Goblins Are Different: Goblins are short-lived and weak humanoids who reproduce quickly, using large hunting bands to take down more powerful monsters for food. Though not very intelligent because of a lack of any means to educate themselves, they are clearly not stupid and have great love for their families. Their goal in life is to live and fight long enough to evolve into longer-lived hobgoblins and aid their family in doing the same. In truth, they're simply modified humans either descended from Gob-Gob or built in his image by D.
  • Our Gods Are Different: Gods are beings whose souls have evolved to the point that they can absorb massive amounts of magical power, allowing them to transcend most mortal restrictions. Entire races capable of becoming gods exist, such as Gyurie's. Angels, on the other hand, seem to be a defense mechanism created by planets to destroy more dickish gods. Titans are the oldest faction and others are indicated to exist, but play no role in the story and are therefore not mentioned much.
  • Our Ogres Are Hungrier: Ogres are an evolution of goblins, which grow larger with each evolution. They tend to wield crude weapons and move in large groups. Wrath was unusual not only due to his weapons and intelligence but also due to being alone. The Oni is a special evolution of the Ogre which looks identical to a human aside from two horns.
  • Our Vampires Are Different: There are two different types.
    • Sophia and those she turns are physically and magically much stronger, but have a tendency to either view humans as food or at least quickly grow uneasily comfortable with controlling them. Walking in the sun is uncomfortable for her kin and all require blood, though it can be taken without turning the victim. They specialize in blood and charm magic.
    • Natural vampires are essentially supernatural rabid animals. Both animal and humans lose their minds but become physically much stronger. They attack and feed on other animals, with a single bite being enough to transfer the infection. Regaining one's mind after being bitten is very rare.
  • Parental Abandonment: Shiraori feels the behavior of "D", who essentially created her, is even worse than this because she fully expected Shiraori to die.
  • Patricide: Ariel kills her father, Potimas, to avenge all the suffering he inflicted on her and her siblings.
  • Perception Filter: Shiraori uses a spell that causes people to only perceive her as "white", forgetting any other feature. Repeated exposure or familiarity with her appearance grants immunity to the effect. Dustin is startled to realize that he didn't even notice while speaking face to face at length.
  • Perspective Flip: The story slowly develops into a reverse of the general isekai plot with the hero being a tertiary character generally reacting to events in the background while the 'villains' are constantly struggling to try to actually fix problems, though they are pretty morally gray at best. Thanks to the story focusing so much on the morally ambiguous villain side, the hero's claim to moral superiority ends up ringing a little hollow. After all, it's easy to stick to your morals when you've never had to make a hard decision, let alone one like 'be a slave or kill the person oppressing you' or 'starve to death, get butchered or be willing to get your hands a little dirty.'
  • Planet Looters: The true dragons chose to depart the world rather than continue their battle with the ancient civilization and Sariel, but took the entire planet's MA energy with them.
  • Please Kill Me If It Satisfies You: The Pope offers this to Sophia as compensation for the war that killed her parents. This has less impact than it first seems as Dustin will just reincarnate and become Pope again. However, the time lost at this critical juncture would still cause a significant problem to his plans.
  • Poor Communication Kills
    • Shiraori is almost completely unable to speak to people she doesn't know well, which is a weakness she doesn't really try to overcome. As a result she alienates a lot of people.
    • If Blow had known that nothing Julius could do could possibly hurt Shiraori, he could have evaded an attack that basically ended the fight. Instead, he tried to shield her and the soldiers with her. Worse, the fight may not have needed to happen or could have at least ended with Shiraori stepping in to save him: Before the fight, he asked her to not interfere because he thought she would just get killed, but she thought he meant it would hurt his pride.
    • On a more comedic note, if Sophia had ever mentioned to Shiraori how she behaves them drunk then she'd have quit drinking in front of her. Shiraori has no clue what a mean drunk she is and is ashamed when she finds out.
  • Post-Modern Magik: "D" communicates with Kumoko via a teleported smartphone.
  • Power at a Price
    • The entire skill system works on this principle. The System forcibly alters people's souls to give them new abilities, and cuts chunks off the soul after death to repair the planet, before reincarnating them for another round of processing. Too many skills in one lifetime or too many reincarnations through the System will eventually result in your soul warping or collapsing completely. Further, the 14 ruler skills are so powerful the modifications they cause on your soul seriously warps your personality if you don't have Required Secondary Powers like the Heresy Nullity.
    • On top of system access rights, the Ruler titles all grant a unique skill such as Enma (from Wrath) or Hell (Pride) powered by what's known as the Divine Area, meaning that if you use them, it will decrease in size. Since the Divine Area by itself seemingly does nothing, this isn't terrible alone until it's revealed that it's basically a measure of your soul's capacity, so using a Divine Area powered skill literally burns part of your soul. Further, gods are beings whose souls would be classified as having a Divine Area of level 10 by the system, so using the skills are making it harder to potentially become far more powerful and free from the negative effects of the system down the line.
  • Power Copying
    • Skills can be learned by observing someone utilizing it and then copying their actions until the Skill manifests. Kumoko can cast unlearned magic spells by manually retracing how the magical energy is configured by the spell while Wrath acquired a sword master's skills by imitating his movements. This becomes an essential skill to defeat the security robots at the underground facility, by copying their anti-anti-magic field.
    • Kumoko learns several magic types by simply watching others cast them, including earth, lightning, wind, water and fire magics, though by this point she doesn't actually need them at all. She gets confused at how Sophia has no clue what she's supposed to be doing when she sets clones to both protect Sophia and to repeatedly cast magic in front of her so she can see how it works.
  • Powered by a Forsaken Child: Skills are created by the System directly manipulating the soul while XP is generated by recycling the soul of the killed and giving part of the energy to the killer.
    • Even worse is the revelation that the deficit between the energy consumed versus the energy available in the System is made up for by directly draining energy from the Goddess. She's being drained to death and Gyurie will be forced to take her spot afterwards.
    • Potimas's robots contain massive amounts of power, which Ariel sadly notes comes from souls. And since souls have a limit on how much energy they can hold, the more powerful robots must contain a lot of them.
    • MA energy, which Potimas and the ancient civilization abused, is in fact the spiritual energy of the world.
  • Powers as Programs: Skills are programs executed by the System to produce desired effects. Something targeted by a skill in turn has programs such as resistances that register the effect and determine the damage done. To a being outside of the System, many attack spells are harmless as they have no actual effect other than what the System registers.
  • Pragmatic Adaptation: Two frequent criticisms of the web novel are that the pacing is very slow with a lot of time spent with Kumoko playing around with skills and that with only her as a viewpoint character the narrative can be a little dull. So in the light novel, there's less time spent sitting around just practicing and the chapters tend to alternate between Kumoko and Shun's perspectives to keep things more interesting.
  • Pretext for War: Kumoko was used as this by two nations and the Divine Word Religion. She really wished they would find somebody else to use as an excuse.
  • Prevent the War: The Elves are constantly trying to maintain a peace between the humans and demons, acting as ambassadors and covert agents targeting dangerous elements. This is solely to match with Potimas's self-serving plan rather than because he believes in peace.
  • Pride:
    • Shiraori's central philosophy. This starts with believing it's not just enough to survive, and if she's going to live she's going to live proud, fighting without running away or giving up on what she wants. This later extends to her discomfort with having to be beholden to D, and trapped within D's plans her whole life. It's also the reason she cares so much for Ariel, as Shiraori sees her as a being with such pride she's willing to challenge the entire world and even the gods to get what she wants. However, while she holds pride to be the most important thing for a person, she knows she fails to live up to her own standards because she won't fight unwinnable battles just for the sake of pride, which lowers her self esteem further.
      Shiraori: In my case, I don’t yet have a belief that I can be puffed up with pride over. I have no pride. That might be the exact reason why I seriously want to help this proud Demon King.
    • Pride is also one of the Seven Sin Skills, and grants the user a massive boost to skill development speed. D notes it's probably the most outrageous skill in the system and the most deadly, as skills and exp warp the soul, meaning pride accelerates the process of losing your sense of self, and ending up Deader Than Dead when your spirit collapses, faster than any other.
  • Prolonged Prologue: The story proper arguably doesn't begin until Chapter 151 when Kumoko finally escapes the Labyrinth; at that point she begins interacting with the main cast and the plot begins to reveal itself.
  • Puppeteer Parasite: Yuugo is being manipulated by a hatchling clone of Shiraori, though she mainly uses it to nudge him in certain directions rather than fully control him.
  • Rage Breaking Point: Kyouya's anger was constantly growing after being tamed, but it was seeing his older brother turned into a tool that laughs about killing his own kind that finally drive him over the edge, unlocking the Wrath skill.
  • Random Power Ranking: Monsters and adventurers are ranked with a letter system, the understanding being that it takes six adventurers of average skill to beat a monster of similar ranking. D-rank is the usual starting point for adventurers scaling up to A- and then S-rank while Kumoko was born as an F-rank monster. Above S-rank is Myth-rank, given to monsters so powerful they can devastate entire armies.
  • Read the Fine Print: In the backstory, D pointed out that Sariel's current plan to save the world was doomed to failure for several incredibly obvious reasons. As Sariel sits there stunned, D then offers an alternate solution: The System. Unable to actually understand the workings of it and at a loss because she has no clue what else to do, Sariel agrees without thinking, only to find that the System relies on constant unending warfare and bloodshed to heal the planet. Given her personality, she is not happy with the solution, but she doesn't (and probably can't after the contract with D was signed) give up on it.
  • Reassigned to Antarctica: After Buirims fails to tame Kumoko, he gets assigned to an isolated village on the Magic Mountain on the border between the Humans and Demons. Unfortunately, it's so inhospitable that nobody guards it, leaving Buirims with little to do other than kill local monsters.
  • Red Herring: There's a lot of implications early on that Kumoko is going to become the Demon Lord, but the timeline doesn't really make sense. But that doesn't mean she isn't part of the Demon Lord's faction. In fact, if anything, she's her boss.
  • Reduced to Ratburgers: The first people Kumoko treats at her healing shrine are a desperate peasant woman and her dying young child. She can see that they both have the Filth Eater title, indicating that they were so poor that they had to eat rotting garbage. To cure them she puts them to sleep, removes their tainted organs and regrows them.
  • Reincarnation
    • The entire class is reincarnated into this world, including the teacher. And a house spider.
    • Pope Dustin the 61st has reincarnated 60 times, his first life having been during the collapse of the ancient civilization. He retains his memory with each reincarnation due to his Temperance skill.
    • Reincarnation without memories is standard for all creatures that possess souls, with a cycle that apparently allows them to be reborn on entirely different worlds. "D" sealed souls in the System so that they are immediately reincarnated on the same planet with no chance for the soul to rest, causing increasing damage as time goes on. The souls inside the System are nearing the point of collapse and causes most of them to be very weak. Thus, the reincarnators are only relatively strong: Long ago, they would have been nothing special.
  • Required Secondary Powers:
    • Poisonous creatures naturally have poison resistance, as otherwise their own poison would damage them. In the backstory, Ariel averted this, since she was a result of her father's experiments and predated the game-like system. As a result, she was barely capable of surviving due to her body constantly suffering from the toxins it produced.
    • Kumoko eventually evolves into a monster that ordinarily dies the first time it uses a Corrosion element attack that it has no resistance to. Luckily, Kumoko developed such a resistance earlier on, after having to subsist on corrosive bugs in a high level monster area.
    • Kumoko susses out that to use Detection she needs to improve her mental fortitude. By acquiring and leveling up abilities related to math and multi-tasking, as well as gaining a resistance to Heresy attacks, Kumoko is able to utilize it.
    • Almost all of the Sin and Virtue skills directly impact the soul, warping the mind over time. The best way to counter them is by acquiring Heresy Nullity, as it prevents the warping. Of course, you can only obtain the skills in the first place if they're already a Fatal Flaw in your character, so you'll still tend to indulge in them.
    • Magic skills can only be activated if the user has the Magic Perception and Magic Manipulation skills. Most monsters, including Kumoko, never learn these skills and remain incapable of magic.
  • Respawning Enemies: A feature of the early days of the System caused monsters to randomly spawn. This can still occur but most monsters have developed large enough populations that they can maintain their numbers by breeding. However, thanks to Kumoko, by the time the story reaches the present the monster population inside the Elro Labyrinth has been so depleted that it's practically a ghost town.
  • Restart at Level One: When a monster levels its class to the maximum, it can then evolve into a new form and return to level one. Doing so seems to lose most of the gained stats, which then rise again slightly faster than the last form did. New skills are generally gained as well. Apotheosis is similar in principle as well: Kumoko lost all of her System derived abilities when becoming a god and had to develop the real form of the spells they were based on. Plus, much to her annoyance, poison magic is not really a thing outside the System, so she can't use one of her greatest strengths anymore. However, while she only has strong aptitudes for dark, corrosion and space magic she believes that she'll eventually be able to reproduce the other magic types in general effect, though she wouldn't be technically using, say, an ice spell.
  • The Reveal: Quite a lot throughout the story.
    • The previous Hero and Demon King teleported into the protagonits' classroom because the evil god who controls their world, D, was on a holiday as a Japanese school student on Earth.
      • Potimas had originally tried to convince the two to kill Gyurie, only for Sariel to forcibly redirect them toward "D".
    • The RPG system everyone uses is just a large scale application of magic created by D for some alternate purpose. This means effects like poison or elemental weaknesses are just complicated magic mimicking game mechanics.
    • The main character, Kumoko, was never a Japanese high school student named Wakaba Hiro. Instead, she was a house spider who was living in Wakaba's classroom. In fact, Wakaba Hiro is actually D, the self-proclaimed evil god of The Underworld, who gave part of her memories to the spider, then reincarnated it somewhere she expected it to die, so when it got to the underworld it would throw her boss/partner off D's trail a little while longer, and she could keep slacking off on Earth. Kumoko instead survived, which D found so entertaining she didn't want to interfere with the spider's exploits, and abandoned her original plan.
    • Shiro/Shiraori, the seeming Big Bad of Shun's side story, is actually Kumoko. And Kumoko's entire story up to the point the side story started was actually set a decade before Shun's.
    • The System is actually a Perpetual Motion Machine that absorbs the skills and experience mortals have gained over their life after they die to do something...
    • The System is actually repairing the planet, as centuries ago humans created Lifestream eating Magitek that literally split the planet in two and killed 90% of all life. Also the previous Hero and Demon King teleporting onto Earth to kill D stole so much energy from the System that it'll fail in a matter of years.
    • The destruction of the world was caused by Potimas, who recklessly angered a faction of gods called "the dragons" and spread technology for abusing MA energy despite being one of the few who knew the damage it could cause. After the dragons devastated the human nations and then stole almost all the remaining MA energy and left, humans tried to sacrifice Sariel to restore the dying planet (though it would have failed due not only to Potimas sabotaging the process, but the fact injecting one soul into another all at once being a recipe for disaster) only for Gyurie to appeal for D's help, resulting in the System being implemented.
    • Which leads to: The System was far from the best solution D could have given Gyurie and Sariel. For instance, D could have trivially repaired the planet herself with her own massive amounts of soul energy, or allowed Gyurie to kill Potimas to make the whole process go much faster. But instead, she imprisons Sariel, tricks Gyurie into doing nothing, and spares Potimas, because it's more interesting to watch that way.
  • Revenge Before Reason: The Anogratch's need for revenge is so powerful they completely disregard the actual cost involved. Kumoko killed or ensnared dozens yet they kept coming, right down to the last member of their troop.
  • Roaring Rampage of Revenge
    • The main danger of the Anogratch, or "Revenge Monkey". They are organized into large groups called "troops", and killing a member will bring down the unstoppable rage of the entire troop on the assailant. Entire forts have been brought down by inserting a single Anogratch as a "bomb".
    • Half the reason Shiraori starts the Human - Demon War is to get back at Potimas for using Oka as a hostage against her.
  • RPG Elements: Similar to other works in the Reincarnation genre, with a few twists. Shun and Katia note it's somewhat worrying that the System has only combat skills and skills that supplement combat; there are no crafting skills or similar.
  • Screw This, I'm Outta Here!
    • Kumoko thinks it's entirely natural for her to run away from an opponent who outmatches her. On the other hand, any opponent she outmatches should be ready to accept death.
    • Shiraori responds to delicate social situations by walking away or, if it follows her, teleporting away. She also attempted to leave the planet after becoming a god but was convinced to stay due to warnings about the dangers of doing so, an offer of divine patronage, and tasty food. The last item decided it.
    • Potimas had a UFO prepared in case he needed to leave the planet. Shiraori caught it easily. He'd originally planned to do this when the ancient civilization was on the verge of collapse but decided to remain when the Skill System was created.
    • The dragons left the planet rather than continue to fight and lose against Sariel.
  • Schmuck Bait: The Ruler titles all grant awesome effects and unique skills, but they're actually incredibly dangerous to the soul of the user. Kumoko only gets away with using them as much as she does because she has high heresy resistance and later nullity, meaning they can't do too much to her.
  • Screw You, Elves!: Both the Pope and Administrators show this behavior towards the Elves. Justified given Potimas is willing to burn the entire world to become an Administrator and the Elves are either his clones, brainwashed abductees, or their indoctrinated children.
  • Sea Monster: The ocean is overrun with water drakes and dragons to the point that even fishing on the coast is near-impossible without encountering one.
  • Seiza Squirm: Shiraori punishes Sue by tying her body into seiza posture. As she'd never sat as such before she was in tears by the time Shiraori released her.
  • Senseless Sacrifice: "D" points out that Sariel's original plan to save the world by being converted into MA energy and directly injected was flawed on multiple fronts. The equipment wouldn't have worked properly, Potimas was almost certainly going to siphon off the energy, and there was a good chance the planet would reject the energy and die even faster.
  • Serial Escalation: Kumoko starts off barely surviving against the various monsters in the labyrinth, forced to rely on webs and ambushes. As the story progresses she moves to hunting larger and larger monsters, then to hunting dragons, and then to taking on the Demon King and Administrators before becoming one herself. At which point she sets her eye on destroying the Skill system.
  • Serious Business
  • Seven Deadly Sins: In the form of Skills, either earned from a corresponding basic skill such as Anger or purchased with skill points. All are very powerful and dangerous as they grant the user "Ruler" status along with immediate rank 10 Skills. They also have a tendency to warp the user's soul. Shiraori is trying to steal the "Ruler" authority for as many of these as possible.
  • Seven Heavenly Virtues: The counterpart to the Sin series, they're just as game breaking and dangerous to the user.
  • Shaped Like Itself: A lot of skills like Divinity Area Expansion don't say anything helpful in their descriptions: For example, Divinity Area Expansion: Expands the Divine Area. Gee, thanks. Maxing out Taboo, on top of its downsides, also appears to expand how much certain skills reveal about themselves.
  • Ship Sinking: Shiraori has three prominent male characters around who are all quickly ruled out. Blow is killed off before we learn he had a crush on her, Wrath's reaction is basically 'ew no' while Gyurie thinks she's interesting to talk to but absolutely not romance material. Also, he's in love with someone else already.
  • Ship Tease
    • So far as Shiraori can tell, Katia is the heroine of Shun's tale, though she finds it kind of annoying. She even uses the power of love to break free of mind control and gets a princess carry afterward. Go die, normies!
    • Sophia and Wrath have a weird slightly shippy relationship, going so far having Sophia flat out proposition him in the middle of an argument. He turns her down, though.
  • Shoot the Dog
    • Shiraori's main goal is to shoot the dog that everyone else has been trying their best not to notice. Thanks to the irresponsible behavior of others, she and Ariel are forced to plan widescale massacres in order to prevent the actual destruction of the world and the soul collapse of everyone on the planet because everyone before her was unwilling to make the kind of hard choice that Sariel wouldn't like. The death (or worse) toll if she doesn't shoot the dog is estimated to be at least 25% of the population, possibly higher up to and including everyone on the planet if the situation destabilizes.
    • Potimas creates clone bodies he can act through by placing a tiny piece of his soul inside them to act as a controlling parasite. Shiraori figures she could maybe remove one or two but anything more is beyond her and is only a guess to begin with. Given how dangerous Potimas is, she elects to simply kill them one by one, including arranging for Yuugo to target the infected when he begins his coup because otherwise Potimas could have destroyed several countries at once by turning their leaders into puppets.
    • Locked in a fight against an unstoppable robot powered by souls, Ariel destroys those souls with Soul Break because she has no way to free them, especially in the middle of a fight. These souls were presumably innocent people once, but now they've basically ceased to exist because of Ariel.
    • Shiraori is the one ultimately responsible for the assassination of Shun and Katia's parents as well as a number of other high ranking members of the kingdom. They had been infected with Potimas' soul parasites, which had to be removed. However, clearing them without killing the person involved would have been incredibly costly and only worked on a single person, so she judged it would be best to have them all killed instead of trying to save just one and tipping off Potimas as a result.
  • Shout-Out
  • Silly Rabbit, Idealism Is for Kids!: Shiraori and Wrath both scorn Shun's more idealistic position when it comes to the necessity of violence. However, while both of them are highly sympathetic and it seems like there may have been no other options, there's a lot of wiggle room for both of them to be wrong and Shun to have been right all along. Namely, there are some obvious holes in Shiraori's interpretation of the world and she could at least be doing a far better job than she is to keep people safe, but she doesn't care. Also, Wrath's former master and Yuugo were not entirely unsympathetic people once you truly understand why they behaved the way they did. A decent attempt at communication may (or may not) have been able to resolve both situations peacefully. Wrath's namesake flaw comes in him not really caring whether someone is redeemable because he sides with the victims who want vengeance.
  • Single Specimen Species: There are no Arachnes at the start of the story and they've presumably never existed either. The same goes for the Zana Horowa, the species that seems most likely to evolve into it. When Kumoko reaches these levels she's the only example to ever live. Even when she uses the Spawning skill as a Zana Horowa she creates a different species line entirely, not more immortal spiders. It's unclear whether she could have made more Arachnes. Though in theory her clones should also be able to shapechange like she does and her true form does seem to still be a spider woman, so perhaps they do exist still. Just not within the System.
  • Single-Stroke Battle: Nyudoz and Wrath's duel consists of Wrath cutting through Nyudoz's sword and neck with a single blow.
  • Space Cold War: It's a background detail of the setting that one of these is currently going on. There are multiple clans of gods, all of whom seem to view each other as rivals or enemies. One important trio has hit something of a standstill: The dragons, the angels and the demons don't openly fight each other anymore due to a roughly even balance of power. Because of this standoff, younger gods don't have the chance to fight anymore like they did when the gods were fighting openly.
  • Spared by the Adaptation: When Shun's group is fleeing the kingdom, they choose not to make the attempt to save Katia's parents with Katia herself arguing that there isn't time. In the light novel it's not a problem because they're with Leston's group and are therefore able to be killed and resurrected to shed Potimas' soul parasites safely. Or "safely" if you prefer. Afterwards, they're promptly put on a bus when Katia bluntly tells them they have no way of stopping her from going to the elf village with Shun and are left behind.
  • Spectator Casualty: Blow blocked Julius' attack spell to shield Shiraori and the surrounding demons, mistakenly thinking she was weak.
  • Spider People: The special "Arachne" evolution has a human upper half stuck on the body of a giant spider. None of them actually exist in the world because monsters are unlikely to meet the class qualifications for the lower stages and even on the rare occasions one does show up they tend to accidentally kill themselves. Even the evolution before it, Zana Horowa, has never actually been seen in the world. To evolve from that into an actual Arachne requires the holder to have the Pride title, which really indicates quite well what they would probably be like if they had ever managed to appear.
  • Standard Evil Empire Hierarchy: The first appearance of the Demon King showcases the entire organization, though some of the roles aren't clear until later.
    • The Emperor: Ariel is the current Demon King, a being of immense power known as the Oldest Divine Beast and the Origin Taratect. She has the appearance of a young girl, but actually has spider powers. She's about as strong as you can possibly get within the System.
    • The Right Hand: Ariel refers to Shiro as her "greatest masterpiece" though she played no real role in her birth or rise to power, even coming into conflict with her at one point. Shiro herself is much stronger than Ariel and the one truly in control.
    • The General: There are ten generals, six or seven of whom are basically 'normal' people. They're all quite sympathetic because none of them want the war besides the fifth general, who is both the least important and only supporting it because he's blindly loyal to anyone who serves as the demon king.
    • The Security Officer: Shiro is assumed by most to be a special forces/intelligence specialist due to her impressive intelligence gathering capabilities and use of the rare Space Magic.
    • The Oddball: Gyurie is the leader of one of Ariel's demon armies, but his troops don't take part in the battle and Gyurie himself is only in a watchdog position.
    • The Evil Counterpart: Eight demon general Wrath was once known as Sasajima Kyouya, the best friend of Shun. He has a strong sense of fair play and a quick temper, though he tries to keep it under control. Unfortunately, his backstory since reincarnating has made him incompatible with Shun's ideals. Notoriously brutal among the other generals.
  • Stealth Hi/Bye: Shiraori has a habit of doing this with Transfer, sometimes appearing just long enough to leave a poorly-phrased message before leaving.
  • Storm of Blades: Wrath stores his extra weapons with Spatial Magic and can unleash them in a rain of fired swords. Shiraori compares him to Gilgamesh.
  • Sufficiently Analyzed Magic: Potimas determined there must be rules governing magecraft if he could only deduce them. Which he promptly did. Shiraori then went and analyzed his antimagic and proceeded to neutralize it.
  • Suicidal Overconfidence: In the middle of Kumoko's fight with Alaba, the labyrinth wasps are still trying to sting her even as giant laser beams and fireballs are flying everywhere. They're nothing more than a minor distraction to her and Alaba also blasts them away without paying any attention to them.
  • Super Breeding Program: Potimas created the base stock of the Elf race by cloning himself multiple times. He then had those clones abduct outsiders and forcibly converted them into the same race. This allowed him to create a viable gene pool which could be expanded with the simple process of abducting yet more breeding stock.
  • Superior Successor
    • After Kumoko lays some eggs in the labyrinth and reincarnating into one to escape Ariel, the eggs begin hatching as (relatively) tiny white spider monsters with stats that are the lowest seen in the story at a mere 3. However, they also have some minor poison, the ability to coordinate and a mindless devotion to mommy, so when hunting in groups they're able to take down much larger prey. When Kumoko sees them again a week later, they're already as strong as she was several evolutions later and every time she sends them out again to hunt for her they come back even more ridiculously strong. By the time the story hits the present day, the spiders now known as horo neias are monsters that even individually are on seemingly on par with dragons. Fortunately, they keep to themselves unless attacked because one order they received before attaining independence was that they shouldn't kill Ronant, leaving them neutral towards humans in general. They also really love mom and cuddle her whenever she comes to visit.
    • While the strength of the horo neias is somewhat a matter of speculation, Shiraori considers her clones weak because it would take three newborn tarantula sized spiders to take out a dragon.
  • Super-Persistent Predator: The monkeys confuse Kumoko for this very reason: She's not much good as a meal given how poisonous she is and is more than capable of defending herself, making it clearly not worth the effort for such a small amount of food. However, it's not about eating her, it's about avenging the monkey she killed earlier. The sheer persistence of the Anogratch monkeys is why they're generally known as Revenge Monkeys and in large numbers can be one of the most dangerous monsters around. They will stop at nothing to kill anyone that injures a member of their group.
  • Sure, Let's Go with That: Shiraori often doesn't bother to correct people's misunderstandings if they're convenient to her. For example, she lets all the reincarnators think she's Wakaba Hiiro because the truth is way more complicated and she hates speaking.
  • Take Up My Sword: When the Hero or Demon Lord dies, the skill is automatically awarded to another individual to take over the role. There exists a secret tracking system which makes people previously defeated by the Hero more likely to become Demon Lord.
  • Taken for Granite: The Petrification attribute allows this, usually seen with the Evil Eye. Basilisks possess this naturally, which resulted in Kumoko spending a while with a stone foreleg. Though dangerous, Kumoko eventually decides it's a bit too slow to be practical because while it's crippling in the long run, in the short term it's not that much of an advantage.
  • Tangled Family Tree: Thanks to Potimas's various experiments in genetic engineering and cloning, and "D" playing around with the monster generation features of the System, quite a lot of disparate characters are technically related. This includes Kumoko, Ariel, Oka, Wrath and Potimas at the very least, with Potimas being Ariel and Oka's father, Ariel being Kumoko's grandmother, and Wrath being the far removed descendant of copies of Ariel's long dead brother Gob. And just to complicate things more, the goddess Sariel is the adoptive mother of Ariel, the first Hero, the first Saint, Gob, and all of Potimas's other first generation of genetically engineered children. And "D" is Kumoko's mother from a spiritual perspective, or Kumoko is her clone, depending on how you want to look at it.
  • The Team Normal: Anna is this for Shun's party, being a relatively sheltered maid. She's less skilled in combat and her stats are much lower than anyone else, but she never quite reaches the point of being The Load.
  • Telepathy: A skill allowing mental communication which Kumoko ignores as there's nobody to talk within the Labyrinth. D and Gyurie read her mind whenever they meet her.
  • This Is Something He's Got to Do Himself
    • The reason Shiraori did not intervene to save Blow's life was so he could maintain his pride, something she feels is more important than surviving.
    Shiraori: I can save [Blow]’s life. However, at the same time that is a deed that will stain the hoodlum’s pride. It’s up to each person which one to choose, but I choose to take pride. Even if the hoodlum dies as a result.
    • Ariel refuses any help from Shiraori when she goes to face Potimas as she personally wants to kill him.
  • Thousand-Yard Stare: Shiraori very pointedly ignores the fact that all of her subordinates eventually gain this due to her heavy-handed methods.
    Shiraori: [regarding a soldier she "reformed"] It’s just your imagination that his eyes look like that of a dead fish.
  • Throw-Away Country: During his rampage, Wrath manages to kill nearly every living creature in an entire nation. The last time it was mentioned was when Shiraori let Gyurie think it was necessary to stop the world from collapsing. It wasn't, but the place didn't serve its intended purpose anyway so having them all die doesn't really hurt anyway and has some other side benefits to the plan.
  • Title Drop: By Kumoko herself, explaining her continued monstrous eating habits even after her evolution into a humanoid form.
    Kumoko: I'm a spider, so what?
  • Tomato in the Mirror
    • Kumoko / Shiraori eventually susses out that the inaccuracies and gaps in her memory are the result of her not being Wakaba Hiiro. Shiraori was an ordinary spider that died in the classroom. Instead, The Evil God D was the real Wakaba. D, who had been skipping out on work in The Underworld, then gave the spider part of her memories and reincarnated it in a place she expected it to die, in hopes it would confuse her bosses enough she'd get to slack some more. Instead, Kumoko survived, which entertained D so much she started helping the spider out with the Wisdom skill and protection from Administrator Gyuriedistodiez.
    • Kumoko had a variant of this when she learned about Administrator "D" and what this meant about the Skill System.
      Kumoko: "This world is pretty fun, it's like a game"? I'm an idiot. If this world is like a game then I'm not the one enjoying it. It's the Administrators who are watching it.
  • Tomato Surprise
    • The contents of Taboo explain a great deal about why Kumoko behaves the way she does and especially about her interactions with the Administrators, but it is kept secret from readers for a long time.
    • Kumoko's plan to usurp the Queen Taratects and Demon King are not revealed until after the first Queen is consumed, which explains a great deal about the change in narrative such as the near-absence of the Parallel Wills.
  • Took a Level in Badass: When a unit hits a certain level they have the chance to evolve into a stronger form. This resets their stats backs down but comes with higher stats than the previous form at an equivalent level and several new skills. For weaker monsters, this occurs at level 10. Stronger ones need to get to 20. Some evolutions are even more difficult.
  • Training from Hell
    • When Shiraori decides to make Sophia stronger, the training is kept at juuuust below the level that won't kill her and includes things like being forced to eat poison, walking from place to place as a toddler until she's at the point of collapse and later even harsher training as she becomes capable of handling it. It works, too: Despite being still only being level three she's more than a match for Wrath, who has evolved multiple times and has sky high stats. She later offers suggestions to Sophia and Wrath on how to protect themselves from the Sin titles with the Detection method being marked specially as 'this one might kill you.' While Wrath's reaction is unimpressed Sophia realizes that she means it from Shiraori's own point of view, meaning it's way more dangerous than anything even she had to go through in terms of training. The two of them choose to literally attack each other's souls instead of going through that level of horror show.
    • She later subjects Felmina and the soldiers under her command to this. She mentally refers to it as "tormenting" and insists it has no connection to the dead look in their eyes.
    • Merazofis subjects himself to this in order to become even slightly stronger for Sophia's sake.
  • Transferable Memory: While pondering her reincarnation, Kumoko muses a more unusual explanation might be she had the memories of somebody else who is still alive transplanted into her. She later learns this is true, as "D" implanted a modified set of her human memories into Kumoko.
  • Truman Show Plot: After learning about "D", Kumoko speculates the point of the Skill System is to entertain the Administrators. Or at least "D".
  • Two Lines, No Waiting: The series also has side chapters that focus on a different set of reincarnated students, which plays out more like the traditional Reincarnation light novel story. What's amusing is watching the B-team have difficulty against monsters that Kumoko was hunting for food years ago.
    • Third Line, Some Waiting: After the B-team meets up with a previously unknown C-team, the B-plot is put on hold. The story instead focuses on bringing the A- and C-teams up to date.
  • Ugly Cute: In-Universe, Shiraori wants to ask the Remnants of the Nightmare what they were babbling to Shun about but the moment they see her they all run up and start cuddling her with the clear attitude of 'we did a good job, mom! Praise us!' so she can't bring herself to scold or question them.
  • Underestimating Badassery
    • When Ronant returns to the labyrinth to commit suicide after hearing that the Nightmare was killed by Ariel he runs into Kumoko. While he recognizes both spiders as being her he's only really interested in the white main body, figuring the black spider next to it is just a normal taratect. It is, in fact, a reborn infant Queen Taratect, the most dangerous kind of monster seen in the story.
    • Inverted in Shiraori's fight with Gyurie. She spends the fight confused as to what he's doing and being extremely on her guard against hidden tricks or secret moves, but by all appearances he's actually a pretty crappy fighter even if he's far more powerful than she is. Which, of course, means it's a straight example in reverse: By all appearances, he assumed the fight would be an easy one since he has much more raw power than her, only to realize that she has no intention of fighting him head on as a result and he's not quite strong enough to force her to.
  • Underground Level: Kumoko was reborn in a massive undersea labyrinth that connects two continental landmasses. It took a long time and many powerups before she can muster enough strength to reach the surface safely.
  • Unique Protagonist Asset: The reincarnated class received three bonuses compared to normal people. "D" felt a little guilty about getting them killed so tried to make sure they'd have an advantage.
    • Aside from Kumoko, they start with a massive number of skill points compared to most people. This is actually due to their souls being stronger than those that are being recycled by the System.
    • The exclusive [n%I=W] skill allows their HP and body to full recover on gaining a level rather than requiring healing. It has a number of other side effects like translating the System's level up/skill acquisition notifications into Japanese for them.
    • Either a completely unique skill or high-level skill that suits the individual's personality, such as Kumoko receiving the speed-boosting Idaten and Sophia being a True Ancestor.
    • Kumoko herself has the unique ability to use Appraisal freely, something that usually causes fierce headaches and physical illness, and other mental skills that are usually too dangerous. This is due to possessing a fragment of D's soul, which gives her a higher affinity with the System and greater resistance.
  • Unknown Rival: Kunihiko feels like this due to Merazofis, the man he wants to kill to avenge his family, seemingly overlooking his existence entirely. In fact Merazofis is well aware of him but can't kill him due to Shiraori making reincarnators off-limits.
  • Unwanted False Faith: Kumoko set up near a village hoping to lure in and eat some adventurers or soldiers. Instead she was mistaken for the Goddess' spider servant and ended up healing more people than she ate. She grudgingly accepted it until people start using her as an excuse to be dicks, after which she just left.
  • Useless Useful Spell:
    • Appraisal is an incredibly useful Skill... once leveled. When first learned it returns barely any information and causes massive headaches, which only get worse with usage and more levels. As a result very few people learn or level it, instead relying on Appraisal stones or a handful of families that specialize in it.
    • Immortality turns out to be this for Kumoko. As she quickly realizes, while it technically keeps you *alive*, it would still leave you at the mercy of whoever defeated you, potentially leading to a Fate Worse than Death or reducing you to Sealed Evil in a Can. On top of this, the one serious fight she gets into after gaining it is against an opponent with magic capable of killing her permanently anyway, and in order to continue progressing past that she has to undergo apotheosis, causing her to lose it along with all her other skills.
    • Status spells and effects are a good way to get around being weak early on, but at higher levels most opponents have increasing resistance to them. Since Kumoko ended up building herself offensively as a quirky status affliction specialist, this puts her at an increasing disadvantage with her normal strengths as she gets stronger. As a result, she switches over to using magic more directly.
  • Victory by Endurance: Kumoko defeats Alaba by using Sloth to slowly drain his stamina until he's too exhausted to fight.
  • Villainous Breakdown: Potimas goes from comfortably smug and mildly sentimental to screaming in panic when Shiraori gets serious. By the time he dies, he's yelling unintelligibly.
  • Violation of Common Sense
    • So many times with Kumoko which allows her to gain many skills, even unconsciously assaulting her body with magic attacks to build resistance. When she sees someone try to emulate her she's absolutely baffled.
    • Her protege, Sophia, has also started thinking like this thanks to Shiraori's influence and even Merazofis has developed a similar mentality.
  • Vitriolic Best Buds: Sophia and Felmina eventually strike up a weird, hostile kind of friendship. Or at least as much as a sociopath and one of her many victims can be friends. Sophia even secretly wants to apologize, but only when she's not being forced to do it because that would be insincere and she does realize that she's wronged Felmina.
  • Wall Run: The 3D Maneuver skill allows this. The skills is redundant for Kumoko as she can already do this as a spider.
  • What a Senseless Waste of Human Life:
    • Julius ponders this after killing Blow, given that both had brothers at home they were thinking of. When seen from Shiraori's perspective hundreds of chapters later, She has the exact opposite view, as Blow died standing proud, fighting for what he believed in and free from the interventions of gods like "D" and herself.
    • Shiraori truly wished that she didn't have to massacre the Demon's First Army because of Sariel messing with her plan.
      Shiraori: Sorry, Argnar. In order to grant the future you wish for the demons, the only option was to abandon you.
  • What the Hell, Hero?:
    • Basgas shouts down Shun first when he uses Appraisal on the Water Drakes while entering Elro Labyrinth and again when he talks to the Remnants of the Nightmare. Either move was incredibly reckless and could have gotten everyone killed.
      Basgas: I should have said it! That Lad's comrades might die by your thoughtless actions!
    • Shiraori becomes openly angry after Sariel interferes with her plan to delete the Hero System by making Shun the new hero, shouting her down for wasting the precious energy demons and humans sacrificed their lives for just to get in the way of the very people trying to save her.
      Shiraori: Just how much do you have to interfere until you’re satisfied! Just how badly will you crush people’s feelings until you’re satisfied! Do you really want to save people’s lives that much!? Why can’t you understand that is exactly what is driving people to their deaths!?
    • When some of the whinier students bitch to the adventurer duo about how much fun they were having in the outside world while they were stuck in the village, Kunihiko explodes that gee it sure is fun to break multiple bones every day and to have your family slaughtered and live for revenge against a man who you can't even hope to touch.
    • Wrath, the most moral member of Shiraori's group by far, is furious with Sophia not just because she was using her Charm abilities on other students to make it easier to feed off them but also because she pretended not to see anything wrong with her behavior.
  • What Is This Thing You Call "Love"?: Shiraori doesn't really understand what she feels for Ariel, though it leads her to try her best to grant Ariel's dearest wish. This is likely due to her originally being a spider, and her human memories coming from D, who has No Social Skills.
  • What Measure Is a Mook?: Despite the deaths caused by Yuugo during the failed assassination of Shun, Oka-chan spares his life. This comes back to haunt her and Shun as it just makes him want revenge. Then Shun tries to spare him again due to Kindness influencing him. Everyone else disagrees and Wrath makes his opinion clear by killing Yuugo.
  • Whole Episode Flashback: After the death of Potimas, an arc was dedicated to the ancient civilization and the events that led to the world's current state.
  • With Great Power Comes Great Insanity: The Seven Sins and Seven Virtues skills give the wielder Ruler privileges and immediate level 10 Skills. However they also grant Taboo levels and warp the soul of the user until they are completely overcome by the skill. Kumoko got away with it because Patience had maxed out her heresy resistance, granting her immunity to the soul warping side effects.
  • World's Strongest Man: Demon King Ariel is the strongest being within the confines of the System, with even her puppets being powerful enough to crush armies.
  • Worthy Opponent: Wrath develops Parallel Will due to the stress of fighting the Sword God Reigar and uses the small bit of control it grants to ask his name and give praise.
  • Would Be Rude to Say "Genocide": The entire elven race is destroyed in the process of hunting down and killing Potimas. The only full blooded elf survivor is Oka-san. The main characters say it was absolutely good and necessary whiiiich might be a little questionable, but then again they aren't exactly claiming the moral high ground anyway. Notably, despite the elves all being clones of Potimas, his followers and indoctrinated captives, they're still clearly individuals who aren't in on the full story of what's going on. Most of them were genuine believers in peace and didn't know what long term peace would do to the world.
  • Xanatos Speed Chess: As Kumoko's precognition and concentration powers increase, battles increasingly take on this flavor because she usually can't afford to take even a single hit. This is compounded with the dragons as most of them have similar skill sets for predicting the flow of battle.
  • Yaoi Fangirl: Sachi Kudou, one of the reincarnated students, was this in her original life. With nothing else to do after being sequestered by the elves, she proceeded to convert most of the other female students to her "rotten" interests. The male student who speaks with their male elf guards is rather nervous regarding how they watch him. However, much to her surprise, she finds that in real life it just doesn't interest her and makes her slightly uncomfortable while all the other girls just eat it up, leaving her oddly isolated.
  • Year Inside, Hour Outside / Year Outside, Hour Inside:
    • Shiraori makes pocket dimensions that slow down or speed up time to create prisons, storerooms, and places to talk.
    • Earth experiences only one year for every decade that passes in the fantasy world.
  • You Can't Go Home Again: Shiraori offers to take Sophia home after the System is dismantled if she wants to go, which Sophia misunderstands to mean that everyone can go home any time they like. This is triply wrong: First, the System being dismantled is a requirement to leaving at all since the [n%I=W] skill binds the reincarnators to the world and the only way to ditch it is to die or become a god. Second, Shiroari offered it to Sophia because she's a friend, but actually taking someone along to another world requires so much energy that she cannot feasibly take more than about two or three people with her. Third, even if she could the students all died. More than a year has passed as well and everyone looks completely different from how they did before, up to and including an outright sex change. There's nowhere for them to actually go. Four students have even died again since then, so their souls have moved on as well.
  • You Do NOT Want To Know:
    • When Sophia asks Shiraori a question about what she intends to do after the end, the conversation eventually turns to indirectly talking about D. When Wrath and Sophia trying pressing her for details, Ariel and Shiraori clam up because knowing about someone like D is just way too dangerous and unpleasant.
    • When Ariel unwisely gets Shiraori drunk, the latter starts pulling something out of personal dimensional pockets, snacking on them and giggling while staring into space. Ariel absolutely refuses to look too closely at what Shiraori is munching on or to ask her anything about it. We don't learn what it was either, but given that it horrified Ariel and that both of them are cannibals, it can't be good, even if the scene is played for laughs.
  • You Have Outlived Your Usefulness: Subverted. The first commander of the demon army is sacrificed when a Queen Taratect is teleported into the battlefield and dies thinking that Shiraori was disposing of loose ends, but she's actually furious because she had really wanted to keep him alive but Sariel screwed her over by refusing to allow the Hero title to expire, so Kumoko had to cause massive casualties to make up for the energy it took to do that.
  • You Have to Burn the Web: Standard practice of adventurers in the labyrinth was originally to burn any webs they discovered. Kumoko was traumatized when as a weak infant her first home met this fate. When this happened with another home after she had become much stronger, she proceeded to annihilate the guilty party. Not long after standard practice became avoiding webs.
  • Your Days Are Numbered: According to Oka's special skill, the students are all fated to die at certain points unless she does something. However, it's specifically noted to be flawed: Shun was supposed to die rescuing Leston, but escaped unharmed and successful. Also, for the majority of students who have skills, they're supposedly going to die from skill deprivation. This is only a problem for them if Shun succeeds. Shiraori intends to protect them all and, even if they die, will definitely shield their souls. And even if that fails, it's implied that D is sheltering the souls of all the dying students as well, even the ones like Yuugo and the three students who died in infancy, none of whom Shiraori would/could have helped.
  • Your Magic's No Good Here:
    • After becoming a goddess, Shiraori realizes that most of the Skill systems magic is a farce compared to actual magic. Most of the System spells are essentially programs that only work because the System registers they should. She has to start learning from scratch as some of the magic she uses has no non-system counterpart.
    • The spell used by the previous Hero and Demon King collapsed because the target was outside of the System. Without the System's assistance the spell was too complex for them to manage and exploded.
  • Zerg Rush
    • A common response from various species of monster including Elro Ferect, Finjegoath and Anogratch, a lesson that Kumoko had to learn the hard way.
    • When stalling Gyurie at one point, Shiraori just throws a bunch of clones at him to waste his time. She herself doesn't bother to appear. From his perspective, the fight takes ten days to get through and leaves him utterly exhausted. Later, during her real battle with him, she has the clones rush him in a different way by having him devour the divine territory supporting him while otherwise keeping their distance. The spider clones gobble away at his power while he can't catch up to them. Just killing a few clones wouldn't matter anyway, so he tries to close on Shiraori and fails.

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