Light comes into the story as a 12-year-old boy from a poor farmer family but was invited to an adventurer party featuring all the world's races as the Token Human and going on adventures. His fellow adventurers treated him kindly because of his Gift "Unlimited Gacha" and because of how miserable the humans are treated, and how strong his "companions" are, Light had no choice but to believe it was sincere.
Then the party reached [Abyss], the deepest and "most evil" dungeon.
At the moment they get through the entrance, the rest of the party openly mocks him, calling him "idiotic" for daring to believe their kindness was genuine, and attack him, trying to kill him. The only reason he had a chance was because they wanted to torture him for fun first.
As he's fleeing, he triggers a teleportation trap that transports him to the very bottom of the dungeon, which is too deep for even his so-called companions to reach. There he soon encounters a level 5000 Cerberus, while his level's only in the double digits. Desperately trying to survive, he activates his Gift, despite so far producing lacklustre results such as "rusty fork" and "moldy bread."
To his surprise, out pops the level 9999 maid, Mei, who proceeds to reduce the monster to paste in a single blow and then turns to swear loyalty to him.
It takes him three years to make his way out of the dungeon and back home... only to find his entire village wiped out "just in case" with his brother and sister having gone missing, everyone else dead, to the last child. So he goes back and spends the next two years building up his strength and plotting revenge.
Backstabbed in a Backwater Dungeon: My Trusted Companions Tried to Kill Me, but Thanks to the Gift of an Unlimited Gacha I Got Lvl 9999 Friends and Am Out for Revenge on My Former Party Members and the WorldOther names is a Web Serial Novel series written by Meikyou Shisui, which was originally released on Shousetsuka ni Narou in 2020; it was later published as a series of Light Novels with illustrations by tef in 2021. A manga adaptation by Oomae Takafumi began serialization in Magazine Pocket in 2021. The novels and manga have been licensed by J-Novel Club and Seven Seas Entertainment respectively in English.
Tropes featured in Backstabbed in a Backwater Dungeon include:
- Adaptation Expansion: The original web-novel only has 6 races, including humans. The light novel and manga have 9, adding dark-elves, ghouls, and centaurs.
- Adaptation-Induced Plot Hole: Downplayed. In the Sasha revenge arc, an elven adventuring party goes after Dark and crew for some kind of unstated grudge, where they attacked him first and he scared them off with some kind of ice spell. The incident itself is never shown in the manga, but the arrogant elf party ignores Dark's warnings and chases his party right into Mera's waiting mouth, with their own "don't even bother surrendering and pleading for your life" rants thrown right back at them.
- Always Lawful Good: The humans, without exception, are all decent, noble, and kind, and purely the victim of unjust oppression.
- Black-and-Grey Morality: Light and his allies are hardly as pure as the driven snow, his former adventuring party made certain of that, but his enemies are so vile that extermination is too good for them.
- Boomerang Bigot: The strongest people in non-human races descend from human "Masters", but they are incredibly racist against humans.
- Break the Haughty: Light's favorite way to dispense justice to his enemies is to first trample their superiority complex to the ground, and then he gets serious.
- Chekhov's Gunman: Light's siblings weren't amongst the deceased in their Doomed Hometown. His sister Yume was saved by Princess Lillith, something that Light repays by joining Lillith's efforts to save humanity from the other races' predations.
- Crapsack World: Especially for humans. All the other races see humans as cheap labor to abuse, at best, there are monsters and dungeons to fear everywhere, and life is short and hard.
- Fantastic Racism: Up to eleven and breaking the knob trying to turn it higher. With the exception of the dwarf race, all the non-humans have such an insane superiority complex that they're outright genocidal to humans, for being "inferior."
- Hate Crimes Are a Special Kind of Evil: Much as he wants revenge on his former "companions," Light will always put that on the back-burner when a human "inferior" gets victimized by one of the "better" races for laughs, and the vigilante justice he delivers is especially cruel.
- Humans Are Special: Only humans can get Gifts, and even then, it's rare. Also the "masters" all the other races are scared of are all human.
- Judge, Jury, and Executioner: Justified. Light always lays down summary judgement on his non-human enemies whenever they engage in hate-crimes against humans. The humans are too weak to deliver justice, and the criminals' native races never will, so it's always up to Light to do it.
- Laser-Guided Karma: For the entire elf race! As he's going after Sasha, Light inevitably comes across the elf kingdom, and notices how horrid the humans, all slaves, are treated, with every last elf, down to the last child, treating the humans as punching bags, at best, while spouting a bunch of Green Aesop like they're going out of style, and proclaiming that the world would be better off if humans didn't exist, thus ending their filthy pollution. As part of a massive Xanatos Gambit, Light arranges a scheme of instant and total Slave Liberation, taking every last human out of the elven country. In less than a week, the elves realize the "pollution" they were complaining about is their own filth and refuse, and without any human slaves to clean up after them, they don't know how to deal with it, the stench bringing in mice, rats, and other vermin, and spreading disease. Light is amused at How the Mighty Have Fallen.
- Loot Boxes: Referred to, as Japanese gamers usually call their equivalent "gacha." The protagonist's Gift is this fantasy world's equivalent of a lifetime free pull of loot boxes, which, as it is shown at the beginning of the story, isn't necessarily very useful, since it doesn't modify the loot box system's odds ratios. It's only after his banishment that he identifies the exact conditions when he can override those odds altogether, making it a Story-Breaker Power.
- Playing with Syringes: The dark elf race has this as their hat. Every single one of them is a Mad Scientist who loves to torture and experiment on other races For Science!, most notably trying to get non-humans Gifts so they don't have to tolerate "inferior" humans any more.
- Self-Fulfilling Prophecy: From what little has been revealed, one of the reasons the other races fear "Masters" so much is they have a tendency to protect/avenge the human race. The fact that their constant abusing and oppressing humans might be what Causes them to do so never seems to occur to them.
- Short Title: Long, Elaborate Subtitle: The localized title, since the original title is very long even by light-novel standards and potentially hit technical limits. The title is 5 words; the subtitle 34. It's so long that Google's search engine can't fit the full title.
- Token Good Teammate: To date, the only non-human race shown with any decency is the dwarve race, as they at least operate on Enlightened Self-Interest. They don't care if adventurers, merchants, etc. are human or not, only if they're competent at what they do. When Dark and party bring in dwarf bandits preying on human merchants, the dwarf government actually punishes the bandits, for messing with the delivery of goods. When word reaches the dwarf leadership that humans are getting murdered in the local dungeon, the top brass goes into full alert and issues a bounty on any information that might lead to apprehending the culprit(s), as messing with the dungeon's adventurers, regardless of race, seriously threatens the local economy."The adventurers risking their lives to bring us loot from the dungeon are our treasure! Whoever these 'adventurer murderers' are, they must be stopped!"
