[[quoteright:197:http://static.tvtropes.org/pmwiki/pub/images/fb36f8bab7a808e7f06a7384b6098d00.jpg]]
[[caption-width-right:197:From bottom to top: Alice Fuji, Gokiburi and Yoriko Tajima]]

A manga done by author Shinya Murata and artist Shinsen Ifuji since 2009 and published on Gangan JOKER, ''Arachnid'' provides an unusual take on the standard shonen FightingSeries, with an interestingly deranged cast and a wide variety of exotic fighting styles.

Alice Fuji does not have a fun life. She's spent the last few years being tormented and abused by her drunken uncle, whilst her unusual mental disorder and dearth of social skills have led to poor grades and a complete lack of friends at school. Then a mysterious assassin kills her uncle, press-gangs her as his apprentice, and subjects her to TrainingFromHell for a few weeks before trying to kill her when her recruitment application falls through. Now she's got an ever-increasing price on her head as she fends off one murderous, arthropod-themed lunatic after another, and the only allies she can turn to are the ''slightly less'' murderous arthropod-themed lunatics.

There's also a spinoff prequel named ''Caterpillar'', which focuses on an assassin named Imomushi who had her own troubles within the Organization a year before Alice became involved.

The main series has ended on December 2015 at 72 chapters. It has been licensed in France since April 2015. Not to be confused with the 2001 spanish horror film ''Arachnid''. Also, for Murata's other takes on people fighting with animal abilities, see ''Manga/{{Jackals}}'', ''Vaia'n Maiden'' and ''Killing Bites''. Yū Sasuga's ''Manga/TerraforMARS'' also deals with this concept.
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!!'''Arachnid and Caterpillar contain examples of:'''
* ABirthdayNotABreak: Alice's mother died on Alice's birthday, just after promising to take her to a theme park sometime.
* AbnormalAmmo: One of the assassins is [[ColdSniper a sniper named Gin Yanma.]] She sits hidden on some building and kills people from afar. [[BoringButPractical Seems simple enough]], but then it looks like her bullets have ''dragonfly wings'' for them to travel farther and faster! Given all that happened so far, it would be surprising if this was just metaphorical.
* AbortedArc: Imomushi comes to Alice's school to question Suzumebachi about her sister's death, implying he's still hiding something important about that from her. Nothing comes out of this because not only Imomushi gets more or less killed with little fanfare and isn't mentioned again, [[spoiler:but Suzumebachi is also killed later]].
* AcademyOfAdventure: A polite way to describe Alice's school. A less polite (though somewhat more accurate) description would be 'death-trap crawling with murderous psychos'. The trope is enforced by the Organization boss, who requires the assassins to fight each other and kill Alice while inside the school. There's even a large incinerator in there to dispose of anyone killed in this bloodbath.
* ActionGirl: Alice and virtually any other female assassin.
* ArchnemesisDad: [[spoiler:Suzumebachi to Alice]].
* AerithAndBob: A girl named Alice and a bunch of people with fake names and who are codenamed after insects.
* AlwaysABiggerFish: The narrative exposition on paraponera clavata ants (aka bullet ants) in ''Caterpillar'' states they're so danguerous a group of army ants would avoid fighting a single one of them. The exposition on dinoponera ants in ''Arachnid'' is practically copy-pasted, except the paraponeras are the ones fleeing.
* AnimalMotifs: ...or rather, an insect motif, each for every assassin. However, given Alice and Imomushi are protagonists, those two get a handful of different spider and caterpillar species motifs for the [[NewPowersAsThePlotDemands sake]] [[CrazyPrepared of versatility]].
* AllMenArePerverts: With or without the Queen's Rule brainwashing, few men in the story aren't always harassing women and [[AllMenAreRapists trying to rape them.]]
* AlmightyJanitor: [[CleanupCrew Shidemushi]] seems to be one. Suzumebachi worked as a mailman before he got promoted to front man of the Organization.
* AndTheAdventureContinues: [[spoiler:The story ends with Alice facing the rape zombie apocalypse that's overtaking Japan. Kabutomushi and Oki are also travelling on their own through the urban wastelands]].
* ArmorPiercingQuestion: Yoriko asks Alice if she, a kind person who wasn't able to kill a bully like her, could really be a murderer. Alice had killed two people in self-defense by then, but lies to preserve their friendship. She feels guilty about it and eventually confesses the truth to Yoriko.
* ArmorPiercingResponse:
** When Kuramoto is talking to Alice about her issues with bullying, Alice insists her troubles are no big deal when compared to people who have it worse. Although she seems to disagree with Alice's reasoning, Kuramoto still protects Alice from being raped, at her own expense, while saying the same. [[spoiler:The truth is that she deeply resented Alice for being so forgiving to people who have mistreated her]].
** Dinoponera asks Alice about how her upbringing was like and if she fought in any wars. Alice and Kabutomushi reply she's a plain schoolgirl who's been trained for less than a month. Dinoponera ''flips out'' at this, angry that Alice could attain her skills so quickly just because of some ability she was born with.
** Alice finally admits to Yoriko that she is a murderer, but Yoriko doesn't think that's an issue after all. Alice is so overjoyed that [[spoiler:she completely misses [[MoodWhiplash Sasori spawing into the room and killing Yoriko right after]]]].
* AssholeVictim: Yoshio, Alice's abusive uncle in the beginning. Given how Kumo's murder of Yoshio prevented him from raping her, Alice is practically thankful to Kumo for it.
* AttemptedRape: Alice from her uncle in the very first chapter, and then Oki from Hibiki's thugs in Chapter 12. The trope eventually escalates [[UpToEleven to absurd levels]], with the entire student body of Alice's school being brainwashed into raping people [[spoiler:and turning the whole country into a massive orgy]].
* AuthorAppeal: ''Arachnid'' is Murata's second manga about people with AnimalMotifs, this time focusing entirely on arthropods. The narrator even explains that the Organization doesn't actually force its assassins to use a bug motif, but they all do it anyway out of a fascination for those creatures.
* {{Badass}}: Most of the assassins have some level of badassery.
* BadassCreed: Alice's "kill before being killed" motto.
* TheBaroness: Akiho in ''Caterpillar'' is a sadistic sexpot dominatrix in a nazi uniform who wants to ruin Imomushi's life for no good reason.
* BatterUp: In chapter 12, some of the people working for Hibiki are holding Nail Bats. It's rather amusing that one of them has a ''[[GolfClubbing Nail Golf Club]]''. Even more amusing when Alice swings it at his face.
* BewareMyStingerTail: Sasori turns out to have a long mechanical scorpion tail attached to her back. [[{{Hammerspace}} How was she even hiding that, anyway?]]
* BigBad: "Army Ant" Sara Kurokawa claims she's the boss of the Organization. [[spoiler:But she is a decoy who follows Kuramoto's orders. And Kuramoto isn't the boss either. Yoriko is]]. "Swallowtail Butterfly" Yanagi Akiho fills this role in the prequel.
* BigBadFriend: [[spoiler:Kuramoto is responsible for the school-wide orgy during the Arachnid Hunt and Yoriko is behind everything]].
* BittersweetEnding: [[spoiler:Alice survives the Arachnid Hunt and solves all the mysteries regarding her past, but to her dismay, Yoriko was in charge of it all and was killed by Kabutomushi. The Organization is still out there and they succeeded in bringing ruin to Japan through a zombie apocalypse. Most of the named characters are either missing or zombified and Alice has to [[AndTheAdventureContinues fight them on her own]], having lost Kumoito and parted ways with Oki. Only her determination to live on keeps this from being a total downer]].
* BladeBelowTheShoulder: Dinoponera has extendable needles inside her gauntlets, which have the immensely painful effect of her namesake's sting. Paraponera and Suzumebachi also use this weapon type.
* BladeOnAStick: Kabutomushi wields a halberd with enough strength to shove people far away and make craters on the ground.
* BladeRun: Dinoponera sits on Kabutomushi's halberd when Kabuto first tries to attack her, then hangs on it to avoid being smashed into the ceiling. Later she also walks on the halberd's pole, too.
* BlandNameProduct: ''[[Franchise/KamenRider Kahen Rider]]''. i.e., Transforming Rider instead of Masked Rider. Later on, ''[[Franchise/SailorMoon Sailor-Force]]'' is shown.
* BlatantLies: A teacher demands to know what Kabutomushi's massive spearlike weapon is. Having used it to shove two people out of the building, she tries to claim it's a mop.
* BluntYes: Hibiki when Alice asks if he had a [[HoYay "deep relationship"]] with Kumo. Oki then bluntly asks if he is gay. [[VerbalBackspace He confirms it but then he backpedals.]]
* BolivianArmyEnding: The story ends with [[spoiler:Alice surrounded by the rape zombie hordes that destroyed Japan and about to charge against them]].
* BossSubtitles: Used in ''Caterpillar'' to introduce each character and their rank. ''Arachnid'' also does it late on the plot with characters who hadn't been seen in a while.
* BottomlessMagazines: There's no concern in-story about whether there is a limit on the thread from Alice's Kumoito.
* {{Bowdlerise}}: The magazine version of Chapter 54 had a scene about how Sasori murdered her own parents, [[{{Gorn}} tearing them open and leaving the organs exposed.]] This got blacked out in Volume 11. Volume 12 has a case of NoSwastikas on chapter 55 where the symbol is gone from Hitler's uniform when he is briefly used to illustrate the idea of charismatic brainwashing.
* BrainwashedAndCrazy: At one point Oki is controlled by Digger Wasp, who gives her a dominatrix outfit and has her believe he is Alice. Oki doesn't seem to notice [[NotHimself how unusual]] "Alice"'s orders (such as torturing her friend Yoriko) are and gladly follows them while not actually being any crazier than she already is. Meanwhile, Sara leads and spreads mindless zombie-like students around for them to overpower and rape her enemies.
* BrickJoke: When asked by a shocked teacher what she is doing with a large spear, Kabutomushi claims it is a mop. Later, Yoriko is seen fending off the zombiefied student mob by swinging an actual mop at them.
* TheBrute: "Sia ferox" Riock.
* TheBully: Yoriko is terribly cruel to Alice in the early chapters, to the point Alice considers killing her, but after the first encounter with Sasori, Yoriko has to keep Alice with her for protection and the two begin to get along.
* ButNowIMustGo: After the Arachnid Hunt is over [[spoiler:and Japan is being ruined by the nation-wide orgy, Alice leaves Oki out of fear that she could turn mad and kill the roach for whatever reason, such as during sex like a widow spider]].
* CarCushion: When Abu gets defeated by Kabutomushi, he's shoved out of a building right on top of a nearby car.
* CarnivalOfKillers: The "Arachnid Hunt" in the main story sets a prize on Alice's head that increases every time one of the participating assassins is killed. In the prequel, Imomushi is also the target of one. The people attacking her carry a series of envelopes with details on how her sister Mika was killed.
* CatchPhrase:
** Alice's "I have no choice but to kill" when she or her friends are in grave danger.
** Oki's excited "It's great to be hated!" when she's having fun humiliating people like a dominatrix.
** Sasori's "A scorpion has three friends" pre-torture speech.
** Dinoponera's "If it's you, maybe you can become my friend" when she has good expectations about her opponents. She's also prone to muttering "mai mi thang!" ("no way!" in thai) [[MadnessMantra over and over]] when panicking.
* CerebusRollercoaster: The manga has [[RRatedOpening a very grim start]], what with poor Alice almost getting raped by her uncle, staring death-from-a-random-assassin in the face and deciding to kill him instead, then forming a bond with him only to get forced into a fight to the death. For quite a while afterwards, though, we're treated to rather lighthearted shonen battles and bug-themed shenanigans in a school. Then the entire student body gets brainwashed into becoming [[RapeIsASpecialKindOfEvil rape zombies]], the quirky characters are all disposed of and Alice has to handle the three last danguerous evil assassins on her own.
* CharacterizationMarchesOn: When Dinoponera is first seen wandering around Alice's school, she looks [[EmotionlessGirl rather quiet and serious]], but then her stoic look from the [[http://www.iibq.com/comic/82012133790/viewcomic216801/?p=36&s=1 last panel of chapter 35]] [[{{Retcon}} became a smug grin]] on the Volume 7 release and suddenly she's all smiles.
* CharlesAtlasSuperpower: Everybody in this series is a "perfectly ordinary" human. You may need to remind yourself of this ''repeatedly''.
* ChekhovsGag:
** A minor one. When Alice is feeling bad about being all hurt and bandaged up with an eyepatch, Yoriko and Oki tell her [[BandageBabe she looks stylish and cute.]] Sara was introduced at around the same time, and much later it turns out she's isn't missing her right eye, either.
** In Kabutomushi's first two battles, Yoriko gets knocked down on her back when Kabuto sends Jigabachi through a wall and falls down a floor when Kabuto destroys the ground below them. Yoriko repeatedly says she thought she was going to die, but Kabutomushi assures her she won't... die just from falling from 3 meters. [[spoiler:Kabutomushi herself is who kills Yoriko at the end of the story, by blowing her off the school's rooftop. That's over 12m.]]
* ChekhovsSkill:
** Oki is able to secrete oil as an evasion ability. Later Kabutomushi explains she taught her to subtly do it when in trouble to leave a trail behind her for Kabuto to follow. It happens even though Oki was brainwashed at the time.
** Alice once secretly uses her thread to put a leash on Oki's neck, so she can listen to her conversation with Hibiki from afar and come to her protection if she fails to negotiate with him. Much later, Alice impressively uses this technique to foil a villain's plans and crush their neck.
* CheshireCatGrin: "Scorpion" Sasori.
* ChildSoldier: Some characters are shown to have been trained by the Organization since they were small. Among them, Dinoponera was the one doing mercenary work in war zones as soon as she was able to carry a gun.
* ColdSniper: The moody-looking Ginyanma, or "Dragonfly".
* CompanionCube: After killing Kumo, Alice spends a week talking to a teddy bear as if it was him, trying to cope with her loss.
* ConvenientlyAnOrphan: Alice wouldn't be in this mess if her mother didn't die. Some other characters are orphans who were hired by the Organization from an early age as well.
* CrazyPrepared:
** Alice to ever greater lenghts, courtesy of her DisabilitySuperpower which is very befitting for a spider-themed string user.
** Amenbo knows how to inflate like a balloon to avoid drowning. You read that right.
** Kabutomushi can survive even seemingly lethal attacks to the heart thanks to her implanted exoskeleton armor.
** Being an experienced mercenary, Paraponera gives Imomushi a lot of trouble.
** Dinoponera's "Concentration Driving Force" ability gives her heightened senses comparable to Alice's. And while it is mentioned Alice's senses can't save her from sufficiently fast attacks, Dinoponera is agile enough to avoid practically anything. This ends up subverted, though, when it's shown Dinoponera is actually really short-sighted when making plans.
* CreepyCentipedes: "Caterpillar" Imomushi, "Centipede" Mudake and "House Centipede" Geji.
* CreepyCockroach: Oki is creepy in a perverted kind of way.
* CuteAndPsycho: Most of the girls in the series.
* CuteBruiser: Oki, Kabutomushi, Geji and Dinoponera. Alice has her moments, but she mostly uses [[RazorFloss string tricks]] to fight.
* DamselInDistress: Early on, Oki fakes kidnapping Yoriko to bait Alice. But later Yori is captured by the Sand and Digger Wasps to be tortured by a brainwashed Oki. She tries to stay out of Alice's fight against Dinoponera, but Dinoponera jumps behind her anyway to get a reaction from Alice. [[spoiler:When Alice reunites with her later, Yoriko is attacked by Sasori.]]
* DarkSkinnedBlond: Riock and Dinoponera.
* DarkestHour: Chapter 61. [[spoiler:Yoriko has been killed and practically everyone has been captured by the student mob or is missing. And Kuramoto began the mind control process on Alice, who still doesn't have a clue of her true intentions. It gets subverted, though, as Alice had already figured out her plans and easily kills her before moving on to fight Suzumebachi]].
* TheDarknessGazesBack: The unknown Organization Boss is represented by a pair of ominous wide eyes staring from out of the darkness.
* DeathSeeker: [[spoiler:Kumo trains Alice so she could kill him.]]
* DefeatEqualsFriendship: Oki is brought along by Alice after being defeated. It helps that Oki turned out to not have kidnapped Yori and just wanted [[PsychoLesbian to make Alice her slave instead of killing her]].
* DeerInTheHeadlights: Alice is shocked when Kumo tries to kill her at the beginning, but then she jumps to chomp his neck off. She later becomes feared for being able to avoid being completely frozen even in such dire situations.
* DecoyProtagonist: [[spoiler:You know that cool looking assassin that keeps Alice in his house? Alice kills him at the end of the first volume]].
* DisabilitySuperpower: Alice's "Congenital Excessive Concentration", which causes her to single-mindedly concentrate on the most inconvenient things. With training, though, it allows her to enter a kind of [[HyperAwareness hyper-aware]] state and formulate battle strategies in seconds, and serves as arguably her greatest weapon.
* DisappearedDad: Alice has been told that her father died before she was born, but Kirigirisu reveals that he's actually alive. The father turns out to be [[spoiler:Suzumebachi]].
* DisneyVillainDeath: Seems to be Kabutomushi's favorite way of dispatching enemies, what with her beetle and spear theme and all.
* DisproportionateRetribution:
** The beginning of the story sees Yoriko and her gang bullying the orphaned Alice. Later we learn that [[spoiler:Yoriko made Suzumebachi murder his own wife because his concern for Ayana and Alice messed up Yoriko's agelessness powers. Yoriko not only is responsible for Ayana's death, but she was beating Alice [[KickTheDog out of spite]]]].
** Having a ChildSoldier background, Dinoponera finds it unacceptable that Alice could get on her level in a matter of days just because of some ability she was born with. She overreacts to that and utterly drops her already twisted {{kawaiiko}} ways to torture and kill her horribly.
** Seeing how Alice had been having a life as miserable as hers, [[spoiler:Kuramoto]] thought she could spare Alice and recruit her. But then she gets to know Alice and finds she is nowhere as cynical as her. Just because of that she decides she ''will'' enjoy ruining Alice's life.
* TheDragon:
** Suzumebachi to the Organization boss. A number of people [[LegacyCharacter have held that title]] in the past.
** [[spoiler:Sara to Kuramoto]].
** Paraponera to Ageha.
* DroppedABridgeOnHim: The protagonist of the prequel, Imomushi, was introduced in ''Arachnid'' with business of her own to take care off. Not too long after, Suzumebachi stabbed Imomushi from behind while she was trying to fight Dinoponera and she apparently died instantly in a most unceremonious fashion. [[HesJustHiding Readers generally assume she didn't die]], but she never gets mentioned again and Hanakamakiri never comes to check on things, either.
* DynamicEntry: Hibiki is fond of arriving from out of nowhere [[ConvenientlyTimedAttackFromBehind with a Rider Kick]]. Later he gets on the receiving end of Oki's dropkick.
* EnfantTerrible: Digger Wasp.
* EvilAllAlong:
** [[spoiler:Kuramoto]] pretends to be a friend to Alice, but turns out to [[spoiler:be the mastermind behind the Arachnid Hunt]].
** [[spoiler:Alice spends much of the plot protecting Yoriko and is heartbroken when she gets killed by Sasori, only for Yoriko to return alive and well later, revealing herself as the real Boss]].
* ExoticEyeDesigns: Alice's pupils and Dinoponera's irises ripple when they concentrate. Sometimes they get both effects at once when they're [[DeathGlare angry enough]].
* ExplainingYourPowerToTheEnemy: Not only the assassins do it, but then the narrator also lectures us on how their powers relate to their insect motifs, not that it helps make much sense of the supernatural ones. Sasori has this routine in which she paralyzes people and ''then'' explains what she did and how much she's going to enjoy slowly killing them. It's also been inverted once, when Alice figures out how Dinoponera is able to concentrate harder than her and then explains to Dinoponera the differences between their methods.
* {{Expy}}:
** Shinya Murata's ''Manga/{{Jackals}}'' already had a spider-themed assassin with a RazorFloss weapon in Turis Spider, who aside from being blonde and older than Alice looks similar to her, down to having the same height and weight.
** Geji is pretty much the cute and cool assassin [[Manga/NoMatterHowILookAtItItsYouGuysFaultImNotPopular Tomoko Kuroki]] would daydream of being. The extra content of volume 8 freely admits this with a parody chapter focusing on the traits they share and a sketch of Geji by the author which is literally Tomoko.
* EyepatchOfPower: Sara wears one over her right eye. Alice wore one while recovering from the battle with Hibiki, but then she looked cute rather than powerful.
* EyesAlwaysShut: Kamakiri acts like this before attacking Alice.
* TheFaceless: Alice's mother during flashbacks, until chapter 48.
* FlashStep: The faster characters frequently [[OffscreenTeleportation appear out of nowhere]] [[NoIAmBehindYou behind each other]]. [[BadassBack And they usually look away from the target,]] [[RuleOfCool just to look cool.]] They do have ''insect'' motifs, after all. It's later exaggerated in chapter 48, in which Alice practically teleports around Dinoponera, who insists in trying to hit Alice from behind.
* FoeTossingCharge: Kabutomushi carves a path through Sara's zombified student mob with no trouble, even when Sara sends giant built men at her.
* ForeheadOfDoom: Yoriko's hairstyle.
* GhostCity: The final chapter has [[spoiler:Japan in middle of a zombie orgy, with people shambling all around and violating anyone they see. But then the epilogue with Oki and Kabutomushi has no one in sight. The city around them seems deserted and nearly every building shows signs of decay]]...
* GoombaStomp: Dinoponera at one point almost impales Hikibi's head, but is distracted when she notices Alice is on the floor above her and just stomps Hibiki instead.
* GratuitousForeignLanguage: Dinoponera sometimes speaks in thai.
* GunsAreWorthless: Some characters do use guns, but hardly get any use out of them and soon completely forget they exist as focus is shifted to the assassins' weird insect-themed abilities and weapons. One exception is Ginyanma, who wields a sniper rifle. How would Alice even deal with a sniper? [[spoiler:By hurling her knife and thinking really, ''really'' hard so it flies through all the ''miles'' to Ginyanma and pierces through her scope and head, ''that's'' how]].
* HairAntennae: Oki, as part of her cockroach theme. They even move while detecting movements around her. Oddly enough, she spontaneously gained those antennae just by identifying with a cockroach she saw back when she was an abandoned baby in a thrashed house.
* {{Hammerspace}}: Kabutomushi hides her Kabuto Horn halberd folded in half under her shirt, but it's still far too big for it to make much sense. Then there's Geji who hits Oki with a heavy filled sock that she was still wearing on the previous page. And also Sasori, who hides a scorpion tail larger than herself under her coat. Hanakamakiri often pulls her scythes from out of nowhere, too.
* HappinessInSlavery: Oki, after her HeelFaceTurn. It helps that Alice isn't remotely interested in having a slave, and just treats her as a friend instead. [[spoiler:Sara also feels this way about Kuramoto.]]
* HardWorkHardlyWorks: Having fought alone in wars during her whole life, Dinoponera expected to find a kindred spirit in Alice, but becomes enraged upon finding out she only recently became an assassin and despite this was able to master her ability in a couple of weeks.
* HellBentForLeather: For whatever reason Anabachi dresses Goki in a {{stripperiffic}} dominatrix costume after brainwashing her. [[http://arachnid-manga.wikia.com/wiki/File:Kabutomushi_and_Geji,_Fuji_Alice.jpg A bonus poster]] features Alice and Geji in their own bondage getups, plus an unamused Kabutomushi in the background, if you ever wondered what they'd look like in those duds.
* HeelFaceTurn: 'Cockroach' Oki, the PsychoLesbian assassin, would be the most obvious example (and overlaps somewhat with HighHeelFaceTurn), though Yoriko, the AlphaBitch who befriends Alice after the latter saves her life, serves as a less extreme case.
* HoistByHisOwnPetard: How Alice has defeated some of the assassins thus far.
** Kamakiri (Praying Mantis) is made into stabbing his chest with his scythes.
** Hibiki gets bounced back into a wall while peforming his strongest flying kick. He feels ashamed enough over it to admit defeat.
** Amenbo (Water Strider) is held underwater and drowned, though she [[BalloonBelly holds long enough underwater]] for help to arrive.
** Despite her best efforts to defeat Alice, Dinoponera still gets tangled up and is forced to stab her own leg.
** [[spoiler:Yoriko]] drops [[spoiler:Alice]] off the school's rooftop, only for [[spoiler:Kabutomushi]] to arrive and blow her off too.
* HotSpringsEpisode: The Febuary 2015 crossover between ''Arachnid'', ''Caterpillar'' and ''Killing Bites''.
* HyperAwareness: Alice, Oki, Sasori and Dinoponera have their own ways of feeling the environment around them and instantly countering any attacks.
* IJustWantToHaveFriends: Alice has been lonely and shunned by people, Oki doesn't seem completely ok with being alone and hated, and Dinoponera, who also grew alone, would like to meet someone she can symphatize with even though she's too deranged and picky.
* IKnowMortalKombat: Hibiki based his fighting style on the [[Franchise/KamenRider "Kahen Rider"]] series, training until he made reliable techniques out of the show's ideas. Riock, on the other hand, took from that show an idea of surviving through brute force alone.
* IdiosyncraticEpisodeNaming: Chapters are named after dialogue or monologues [[TitleDrop said in them.]]
* IdiotBall: For a while Alice is made to look like the Arachnid Hunt caught her completely unprepared despite her having heard from Sasori something was going to happen, but she eventually reveals she did spend the past week setting traps everywhere inside the school.
* ImpaledWithExtremePrejudice: Dinoponera repeatedly impales people not necessarily to kill, but to have fun watching them scream because of her stings' [[ToThePain "24 to 48 hours of great pain"]] venom. Alice in particular gets stabbed all over her arms, legs and butt just because Dinoponera was that much pissed off at the time.
* [[ImplacableMan Implacable Woman]]: Dinoponera steamrolls everyone on her way to meet Alice, completely [[NoSell unharmed by anything she couldn't block or dodge.]]
* ImprobableWeaponUser: If an Organization assassin uses a weapon, it'll be an extremely weird one. Alice's WeaponOfChoice, for instance, is the "Kumoito", or "Spider's Thread", a length of spider-silk with a hooked blade on the end that works rather like a cross between RazorFloss and a GrapplingHookPistol.
* ImOkay: Only five "insects" are dead by the 40th chapter, a few of the recurring characters even say so after getting back up from the ground.
* InadvertentEntranceCue: One scene has Imomushi stating she didn't necessarily come to Alice's school to fight her but is interested on the reward on her head. Cue awkward silence as Alice enters the room.
* InsectQueen: Sara, who is Army Ant-themed, can dominate weak-willed people and is followed around by brainwashed minions. [[spoiler:Turns out she's tasked with guiding them, but isn't the one doing the brainwashing...]]
* InstantExpert: The defining trait of Alice's C.E.C. ability is not the "time-stopping" concentration, but this trope instead. She learned all the assassination skills Kumo ever knew in only two weeks.
* InvoluntaryGroupSplit[=/=]LetsSplitUpGang: When a bunch of assassins invade Alice's school to kill her, all she wants is to get her friends out of there, but they keep getting separated for a reason or another.
* {{Irony}}: The two times Oki ordered an opponent to be her slave, she became enslaved instead.
* ItsPersonal: Hibiki hates Alice because she [[spoiler:killed Kumo. He doesn't realize Kumo forced her to do that.]]
* ItRunsOnNonsensoleum: Other than Kabutomushi and her implanted armor, most of the characters don't seem enhanced. But even when their tricks are just plain supernatural, they're able to do them because they somehow fit in their insect motif, without any further explanations other than [[HandWave "they did special training"]].
* JapaneseBeetleBrothers: Kabutomushi is a girly, intense and incredibly strong rhino beetle lady. ''Caterpillar'' has four Stag Beetle-themed people trying to pick on her.
* JusticeWillPrevail: Having watched a little too much tokusatsu shows, Hibiki claims to fight for justice and love, and regards his opponents as evil.
* {{Kiai}}: Hibiki repeatedly shouts [[ThePowerOfLove "LOVE"]] [[http://mangafox.me/manga/arachnid/v05/c024/31.html while stomping people]] and Dinoponera [[EvilLaugh laughs madly]] when pummeling faces.
* KickTheDog:
** Rape attempts for the heck of it cover over half of the series' antagonists. Even a guy like Hibiki who is a justice-obsessed KnightTemplar and who emulates a guy who wouldn't rape or brutalize his victims attempts to get Oki and Alice raped.
** Dinoponera kills a poor employee of Alice's school for no reason when she greets Kabutomushi, showing that for all of her talk of wanting friends, she's an unreasonable bitch who feels contempt for normal people. She's also excessively cruel to Alice when she discovers the spider girl's cheesy InstantExpert skills.
* KillingIntent: When in danger, Alice puts all her focus on how she can kill or at least terrify her enemies. Only Suzumebachi [[KnowWhenToFoldEm gets her afraid enough to flee once.]]
* KnightTemplarParent: Alice's father is implied to be one.
* LanternJawOfJustice: "House Cricket" Hibiki and "Sia ferox" Riock.
* LateArrivalSpoiler:
** The cover for Volume 11 depicts Sasori with her surprise scorpion tail. Volume 12's cover heavily hints at a big plot twist, but at least it had already been revealed in the end of the previous volume.
** Chapter 59 of ''Caterpillar'', first released while ''Arachnid'' was nearing its end, spoils the major plot twist of [[spoiler:Yoriko being the Organization boss, though it doesn't refer to her by name or explain how she came to be this way]].
* LimitedWardrobe: Alice pretty much stays in her school outfit.
* LittleMissBadass: Alice, Oki, Kabutomushi, Geji, Dinoponera, Hanakamakiri and also Imomushi in her childhood.
* MadScientist: Jigabachi, who installed the mechanic tail on [[spoiler:Sasori]].
* MajorInjuryUnderreaction: People who get injected with Dinoponera's venom seem to endure it impressively well after a few moments of thrashing and screaming. Word has it that real life dinoponera or paraponera venom hurts like hell for around 8 hours and lasts for over a day. Dinoponera claims her venom is worth a ''thousand'' stings, so its understandable for her to be surprised at [[MadeOfIron how tough]] her fellow bug assassins turn out to be.
* MakeMeWannaShout: While bored from fighting Hibiki, Dinoponera suddenly stuns everyone in the corridor with a loud scream. [[spoiler:She does it again later to escape after being defeated by Alice, but Kabutomushi isn't affected and almost crushes her.]]
* MaleGaze: Lots of it.
* TheManBehindTheMan: Sara is behind Suzumebachi [[spoiler:but Kuramoto is behind her-- no wait Suzumebachi is actually behind them both. And behind him is the real Organization boss, Yoriko]].
* ManlyGay: Hibiki.
* MartialPacifist: Despite her killing instinct, Alice would rather not kill people and fights only to protect herself and the few friends she has.
* MercyKill:
** Alice does this to [[spoiler:Kumo]].
** Caterpillar to one of Bullet Ant's victims.
* MissingMom:
** Alice's mother, who was supposedly DrivenToSuicide after too much stress.
** Apparently, Yoriko's mother died while giving birth and her father is always away.
** Oki was left abandoned in a trashed home as a baby before being taken to an orphanage.
** Dinoponera's mother died from gunshot wounds while protecting her baby daughter.
* MyKungFuIsStrongerThanYours: The battle between Alice's C.E.C. and Dinoponera's C.D.F. concentration abilities, which turn out to be partially the same thing. Dinoponera gets pissed off at how Alice can learn [[InstantExpert in a couple of days]] something she's [[HardWorkHardlyWorks been training for most of her life.]] Seeing how reckless Dinoponera is becoming, Alice unabashedly rubs on her face how easy it is to read and copy her.
* NearDeathExperience: This trope tends to trigger the killer in Alice, while Dinoponera is shown on a flashback awakening her own concentration technique to survive an ambush, at [[ChildSoldier a very young age]].
* NoSell: Dinoponera seems immune to blunt damage. She gets blown away by a kick to the face and then just stands up with [[SmugSmiler a smirk]]. After this she gets stomped countless times and just gets a bit embarrassed, without damage even to her clothes.
* NotWhatItLooksLike: After Oki defeats Geji, she undresses her to take her clothes, since Oki had [[ItMakesSenseInContext been dressed on a dominatrix getup by Digger Wasp.]] Alice, who didn't know anything, finds her doing this and gets disturbed. Because she's ''[[LesYay jealous]]''.
* OlderThanSheLooks:
** Kabutomushi is said to be an adult in a teen's body. How and why she's like this isn't explained, but it might have something to do with her cyborg-esque enhancements.
** [[spoiler:Once Yoriko reveals herself as the boss, she claims she's over a ''hundred'' years old]].
* OnceMoreWithClarity:
** Some scenes involving [[spoiler:Kuramoto]] are later retold from her perspective, showing what her true intentions were.
** One early flashback is framed as Yoriko thinking back to when her father left her, but that actually was [[spoiler:her adopted son]].
* OrphanageOfFear: The Orphanage Miki[=/=]Imomushi and Mika lived in. The employees beat Miki up for making trouble at school and the director's daughter, who goes on to become the main villain, sexually abuses Mika for years in exchange for Miki not being sent to a reformatory.
* {{Otaku}}: Hibiki and Riock are obsessed about the Kahen Rider show. Dinoponera doesn't go about it like them, but is still rather disappointed that Japan isn't populated with magical girl warriors like in the ''Sailor-Force'' anime she watched as a kid.
* PeoplePuppets: Alice can trap people with her threads to force them to move against their will. And if she happens to be paralysed, she can pull herself around too. She calls it [[GratuitousItalian "Marionette del Ragno"]] in chapter 49.
* PoliceAreUseless: As per usual for a setting with a omnipotent secret crime syndicate, but consider this: the Organization has more than a dozen assassin people get into a school in broad daylight to murder each other and a certain schoolgirl. Classrooms get loudly wrecked, people get shot off the building into the streets and some have no qualms about harming the civilians, resulting in all the male students turning into brainless rapists who cause a school-wide and beyond orgy over the rest of the day. Not only this goes unnoticed by the outside world but they also totally expect to cover something of this scale without any repercussions.
* PosthumousCharacter: [[spoiler:Kumo's]] commentary on some characters' abilities is remembered by those who knew him.
* {{Prequel}}: ''Caterpillar'' takes place a year prior to ''Arachnid''.
* ProfessionalKiller[=/=]PsychoForHire: The insect-themed assassins.
* PsychoLesbian: Gokiburi sets a standard when she tries to make Alice her slave and have her crawl naked around the school. While she softens up from becoming good friends with Alice, villainesses Army Ant Queen and Ageha go much further with the trope.
* RapeIsASpecialKindOfEvil: A lot of the bug assassins cement themselves as evil by attempting to rape someone or get them raped by someone else. They are also the ones most likely to fall victim to some CruelAndUnusualDeath later.
* RooftopConfrontation: Alice fights her master and father figure Kumo on the top of a building. [[spoiler:[[BookEnds At the end of the Arachnid Hunt]], she confronts her evil disappeared biological father, Suzumebachi, on the rooftop of the Ouran High School]].
* ReallyDeadMontage: After Sasori poisons [[spoiler:Yoriko]] to death, Alice cries over her body while reminiscing their times spent together. [[spoiler:It doesn't stick.]]
* SailorFuku: Dinoponera likely wears one to look like a [[Franchise/SailorMoon Sailor Scout]]. The other girls don't anymore.
* ScaryScorpions: Sasori revels in [[TheParalyzer paralyzing and torturing]] people to death with her poisons.
* SeriousBusiness:
** Somehow, this Organization of hardened assassins ended up bug themed because they all simply like bugs. One character even claims that determining which insect is the strongest is mankind's greatest question.
** Hibiki and Riock fighting over who is best fit to be a real-life Tokusatsu hero. That the in-universe equivalent of Creator/ShotaroIshinomori is a bug assassin and Imomushi's master does give them validation.
* ShadowArchetype: From her looks to personality, backstory and abilities, Dinoponera is pretty much Alice with a more physical fighting style and whose lonely background as a child mercenary made her [[{{Jerkass}} mean and deranged]].
* ShaggyDogStory: The story spends over 2 volumes on Dinponera's time as the primary antagonist and her [[InsaneTrollLogic stupidly violent]] attempts to make friends. But after Alice defeats her, she doesn't get to [[DefeatMeansFriendship reason with and befriend Dino]] or beat some sense into her or anything. Instead, [[spoiler:Sasori ambushes Dinoponera and gets her gang raped by the army ant students. [[PutOnABusToHell And then she's never seen again]]]], making her participation in the plot depressingly pointless.
* ShooOutTheClowns: The entire supporting cast gets PutOnABus by way of being cornered by a mob of zombie-like brainwashed students who want to rape them, so Alice has to fight through Sasori, the Army Ant Queen and Suzumebachi all on her own.
* ShoutOut:
** The series has a couple [[ProductionThrowback production throwbacks]] towards ''Manga/{{Jackals}}''. Alice borrows a lot from Turis Flag and Abu uses Isaac's "Brand Nero" fighting style.
** The [[Franchise/KamenRider Kahen Rider]] and [[Franchise/SailorMoon Sailor-Force]] [[ShowWithinAShow shows within a show]].
** Geji [[{{Expy}} looking and to some extent acting]] like [[Manga/NoMatterHowILookAtItItsYouGuysFaultImNotPopular Tomoko]] is adressed in a parody side chapter.
** Chapter 45 of ''Caterpillar'' has Inaho Enoki [[TheCameo from fellow bug manga]] ''Vector Case File'' discussing bark mantises. Chapter 46 has the [[NoCelebritiesWereHarmed in-universe equivalent]] of ''Kamen Rider'' creator Creator/ShotaroIshinomori talking about crickets.
* SkywardScream: Alice after [[spoiler:she kills Kumo]].
* SmugSmiler: A frequent expression on female antagonists such as Sasori, Geji and Dinoponera.
* SmugSuper: Each insect assassin is more arrogant than the last. They also tend to get messed up very badly by Alice, who herself has done epic boasts on how spiders are the pinnacle of arthropodkind.
* SomewhereAnEntomologistIsCrying: The series greatly exaggerates insect qualities for the sake of justifying the superpowers of the assassins. And unlike how all the enemies are based on a specific species, [[NewPowersAsThePlotDemands Alice jumps all over the place when analogies are made.]] One chapter she's an Araenid, the next she's a Salticid.
* SpidersAreScary: Alice normally is [[BewareTheNiceOnes a gentle and kind girl]], but in battle she becomes much colder and creepier.
* StrongAnts: Some antagonists are ant-themed. "Army Ant" Sara is helpless in battle but [[TheMinionMaster turns the entire student body of her school into her brainwashed minions.]] Dinoponera comes equipped with poisoned stings and is shown to be greatly strong, fast and resistent. The prequel has Dinoponera's foster father, Paraponera (Bullet Ant), being a difficult opponent to Imomushi who survives a grenade exploding in his face.
* SuperDrowningSkills: Alice can't swim. Good thing her sports teacher Shinobu is willing to help her learn, huh?
* TheSyndicate: "The Organization", which targets people they deem worthless to take over their identities and commodities. They pick people who have nothing to live for and turn them into cold-blooded assassins with bug motifs. And of course, they have much control over the world and are untraceable.
* TakeThatKiss: Dinoponera suddenly hops near Alice and kisses her, telling her to pay attention. The motionless Alice's stunned, blushing expression [[LesYay speaks volumes]], especially considering what her [[ForcedKiss previous kiss]] [[AttemptedRape was like.]] However, Dinoponera is a very danguerous person trying to pick a fight with her and [[ClingyJealousGirl Oki is right there screaming in rage.]] Dinoponera then notices Oki and just happily ''[[SmugSmiler glances]]'' at her. It's made even more [[AwkwardKiss awkward]] by how not long before this [[ShipTease Alice had accused Oki of cheating on her.]]
* TalkToTheFist:
** Hibiki starts a hated argument against Riock over who between the two of them is worthy of the Kahen Rider title but Riock quickly sucker punches him through a wall.
** Alice brags to Dinoponera she just needs two or three days to surpass her concentration power. Dinoponera defensively crosses her gauntlets and cries that she won't even give Alice the chance, but is interrupted by her blade suddenly being forced by strings into her leg.
* ThatWasNotADream: After Alice beings Oki home, she dreams about the roach girl sweating oil to bypass the sound detection of her thread and then shooting Yoriko to death. [[CatapultNightmare Alice wakes up]] to see that Oki really escaped from her with that bizarre method... but only [[PantyThief to play with Alice's panties]].
* TheseHandsHaveKilled: Alice may be determined to kill when necessary but feels guilt over it.
* TimeStandsStill: Alice and Dinoponera can freeze time by thinking really hard, or at least [[SuperReflexes their perception of time]] is what slows down. They're able to [[FlashStep teleport around]] at the drop of a hat, but aren't immune to people attacking them quickly enough.
* TooPowerfulToLive: The excuse [[spoiler:Kumo]] uses to fight Alice to the death.
* TookALevelInBadass: Alice every now and then.
* TheUglyGuysHotDaughter: Dinoponera to Bullet Ant, but she's adopted.
* UnPerson: The Organization owns all records of their members' existances and is able to erase those if they die. Alice refuses to join them to avoid becoming like this.
* UseYourHead: Imomushi's main attack is to catapult herself head-first on enemies.
* UsedToBeASweetKid: A sizable number of the villainous bug nutjobs get a miserable backstory to explain why they had to work for the Organization to keep living, but on occasion it turns out they were sadists even as children.
* WebcomicTime: 54 out of 72 monthly chapters all happened over the course of a single afternoon.
* TheWorfBarrage:
** Alice often pounces at her enemies like a salticidae spider, but beyond ripping off a chunk of Kumo's neck at the beginning, she always gets knocked away before she can do any harm.
** Any attempts by Kabutomushi and Hibiki to harm Dinoponera. She dodges through her Kabuto Slide and either blocks or completely shrugs off his Rider Kicks.
* TheWorfEffect: Oki claims she's the fastest among the assassins, yet gets easily beaten when someone turns out to be more danguerous than her. Kabutomushi and Imomushi, as strong as they are, can't harm Dinoponera at all. Dinoponera goes on to casually slap around some other assassins only to also fall victim to this trope when she meets Sasori.
* WhamLine:
** Prior to the Arachnid Hunt, Suzumebachi saying the Organization boss is lurking in the Ouran school.
** Dinoponera telling Alice about her Concentration Driving Force is more of a in-universe example, as she had practically spelled it out earlier and her role as an EvilCounterpart[=/=]ShadowArchetype look-alike to Alice make her having some sort of HyperAwareness ability rather obvious.
** Sasori telling Alice she's going to die to her poison like [[spoiler:her mother did]].
** [[spoiler:Yoriko admiting she's the boss and explaining that, among other things, she has lived for over a century]].
* WhamShot:
** Sasori killing [[spoiler:Yoriko from out of literally nowhere, [[MoodWhiplash right after Yoriko told Alice she doesn't think badly of her for having killed before]]]].
** [[spoiler:Kuramoto]] revealing herself as the the true Arachnid Hunt mastermind.
** Suzumebachi looking at a locket with a picture of [[spoiler:his daughter and ex-wife-- [[LukeIAmYourFather a baby Alice and her mother]]]].
** [[spoiler:Yoriko]] coming back from her supposed death with uncertan motives.
* {{Yandere}}: PlayedForLaughs when, after befriending Alice, Oki tells her she would kill any boys Alice liked.
* YouKilledMyFather:
** Kumo killed Alice's uncle but since he was an abusive asshole who was about to rape her, she doesn't care. However, when Alice figures her mother's suicide must have been staged by the Organization, she vows to kill the ones responsible, which turn out to be [[spoiler:her own father, Suzumebachi, who killed his ex-wife with poison he got from Sasori]].
** Imomushi killed Paraponera, who was Dinoponera's foster father. Dinoponera doesn't mind it, glad that her father died in battle against a WorthyOpponent.
* ZombieApocalypse: The disturbing sex-induced mass brainwashing that happens among the students during the Arachnid Hunt, with the Army Ant Queen as their leader. [[spoiler:The situation worsens until the story ends with Alice facing a country-wide rape zombie apocalypse on her own]].
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