The story takes place in a magical world, where the main protagonist Kelvin woke up one day, with no memory of his past life, having traded those memories in exchange for becoming a powerful Summoner. He sets out to explore this new world as an adventurer, gathering new friends and enemies along the way.
This Light Novel contains the following tropes:
- Adaptational Consent: Kelvin's battle slave Efil falls for him and approaches him for sex. In the original Light Novel he accepts the offer; however, in the anime adaptation, he pushes her off him after having a Heel Realization about the power dynamics between master and slave, and resolves to put her in her own bedroom when he eventually buys a house.
- Art Shift: The fight between Kelvin and Gerard is depicted in CGI animation.
- Asshole Victim: The only humans that are killed by Kelvin and his team are thugs, slavers, rapists, and so on. Enemy soldiers who are Just Following Orders are neutralized with non-lethal force.
- Badass Crew: We have an all-powerful mage, an Elf maid with high fire magic and archery proficiency, a Black Knight and a Demon princess. Then there is the slime monster and a literal goddess.
- Bag of Holding: Clotho can act as this, thanks to its skills.
- Bare-Handed Blade Block: Being an expert martial artist in this world means you can deflect sword blows by punching them.
- Comically Invincible Hero: The protagonists keep facing opponents that are much weaker than they are, which is usually Played for Laughs, especially since said opponents tend to be be Smug Snakes.
- Cute Slime Mook: Clotho, Kelvin's first summoned monster. At least when it's not a Glutton Slime.
- Divine Date: Kelvin's primary love interest is Melvina, the goddess who reincarnated him. He falls for her while going through Character Customization, and she eventually creates a humanoid avatar and starts living with him as his wife.
- Failure Hero: The reason Kelvin is summoned to the other world in hopes to whip the previous heroes into shape since their growth are dangerously underwhelming.
- Forced Orgasm: Being affected by the Skill Eater seems to overwhelm the victim's senses to that of a sensory overload that causes this, as shown when Kelvin uses it on Miyabi, and she lets out a huge moan before collapsing to the floor while blushing and panting, claiming she was Defiled Forever.
- Humiliation Conga: Starting with Kelvin disfiguring his face, Clive loses both his legs, gets betrayed by the country he worked for, is stabbed repeatedly by his own Amazon Brigade with hundreds of cursed weapons while never being allowed to die, fuses with said cursed weapons to become a crazed, living Swiss-Army Weapon, gets his body destroyed by Sera and has his soul trapped forever inside a sword to be wielded by his personal nemesis. Of course, given that he is a narcissistic, serial date-rapist who brainwashed countless women into becoming his minions and sex-slaves and treated them as disposable pawns, plenty of people still think that he hasn't suffered enough.
- Inhumanly Beautiful Race: Elves are naturally beautiful, to the point of even having elven blood can make one a Head-Turning Beauty.
- Leaked Experience: Kelvin and his party utilize this method to great effect in order to level up not only the initially-weak Reon whom Kelvin recently brought into the world via the ritual he did earlier to summon her, but also for both his maids Ellie and Luca so that, should the unexpected occur, they aren't completely defenseless in a surprise encounter with an enemy. Clotho, Gerard and Sera compete for who can kill the most hostile monsters in the forest where Kelvin, his two maids and Reon make a temporary safe picnic site at and their levels start leveling up a good deal for Reon, Ellie and Luca as Clotho, Gerard and Sera easily eliminate all hostile monsters in the forest.
- Lighter and Softer: The anime cuts back on a lot of the blood and gore in the Light Novel and manga, as well as recognizing the Questionable Consent aspects of Kelvin and Efil's relationship and applying Adaptational Consent.
- Pass the Popcorn: Zig-Zagged in that it's Kelvin's party enjoying delightful picnic-style foods such as sandwiches whilst watching Kelvin own the entire hero's party by himself by setting up events to make it look like he's the leader of the Bandit stronghold. They eat up with gusto whilst watching Kelvin's fight.
- An Offer You Can't Refuse:
- Leo, Parth's Guildmaster, tends to do this when he gets the chance to hold something over Kelvin's head, although he never goes too far. Kelvin accepts them, knowing he's better off. When he learns Kelvin is a summoner — something he's been hiding to keep himself away from politics — he offers Kelvin the chance of a rank increase, as long as he helps protect Parth from monster attacks.
- After Kelvin beats the crap out of a Tracyn prince, Leo "offers" Kelvin to help wash away the potential trouble if he goes investigate rumors of an S-rank demon in a nearby dungeon.
- Mugging the Monster: In episode 6, a bunch of thieves attempt to ambush the travel wagon Kelvin and his friends are riding, thinking they'll make an easy loot-grab. You can guess what happens to said thieves after messing with Sera, the main female bandit leader pissing her shorts after Sera quickly dispatches of her henchman, quickly leading to their capture.
- RPG Mechanics 'Verse: Characters have measurable stats and SP that they can purchase skills with, and popup text windows appear in the air. The Light Novel even comes with stat cards for the main characters in each volume; the anime displays these as Ad Bumpers.
- Screw This, I'm Outta Here: One of Cashiel's party members decides to run away when he realizes Kelvin is hiding something. Kelvin summons Clotho to stop him.
- Slow Life Fantasy: Kelvin is the Hero of Another Story to a party of stereotypical JRPG heroes summoned to this world by the same goddess. Unlike them, he's not terribly interested in battling the Demon King and chooses instead to make a quiet life for himself in the world, hunting monsters for the Adventure Guild to pay the bills. He only once involves himself with the heroes when they happen to cross paths—and that because he's a Blood Knight who thought it would be fun to fight them (and because their mutual goddess Melvina, one of the members of his harem, asked him to check their skill level and offer some pointers).
- Standard Fantasy Setting: With dragons, elves, monsters, and demons.
- Summon Binding: Summoners like main character Kelvin control monsters via summoning contracts that bind them to the summoner and allow them to feed on the summoner's mana. Nonsentient monsters like the slime and worg he captures have to be beaten down and then captured with the contract magic, while intelligent monsters like Revenant Zombie knight Gerard and demon princess Sera have the capacity to give verbal consent (Gerard wagers his consent on a fight with Kelvin, while Sera agrees in exchange for Kelvin protecting her from the current Demon Lord).
- 24-Hour Armor: Gerald is always seen in his armor. At first, it was justified since he was undead but in flashbacks, it was revealed that he always wears his armor even as a human. He was even seen sunning on a beach while in his armor.
- Warm-Up Boss: Cashiel and his party (who become stronger by fighting and killing other adventurers) becomes Kelvin's first serious fight.
- Wistful Amnesia: Kelvin forgot everything about his world but when he ate something resembling rice, he felt nostalgia.
