Light Novel / Juuni Taisen
Every twelve years, an organization hosts the Zodiac War — a deadly battle royale where its participants must be cunning, crafty, and above all willing to kill to reach the top. Twelve brave, determined warriors who bear the names of the signs of the Eastern Zodiac fight each other for their lives and souls, using a wide variety of powers to augment their chance of success. Beginning with ingesting poison Beast Gems, the participants have 12 hours to kill the rest of the members to get the antidote; only then can the victor of this tournament receive their coveted prize: to have one wish granted, whatever that wish may be.

Juuni Taisen (Lit. "The War of Twelve") is a Light Novel written by NisiOisiN and illustrated by Hikaru Nakamura. An anime adaptation by Graphinica has aired for the 2017 Fall Season, with Nisio stablemate Akira Akatsuki drawing a manga adaptation of the book in September of the same year. Funimation's Simuldub premiered on October 18th, 2017. Watch it here.

The book received a sequel, Juuni Taisen vs. Juuni Taisen, in November 2017.

Everybody, clap your hands!:

  • Action Girl: Toshiko Ino/Boar is easily the most physical of the four female fighters.
  • Adaptation Expansion: In the novel, Boar mentions she killed her sister in order to take the role for the current Zodiac War. The anime adaptation turns this into a Flashback showing how she manipulated her sister into an insane killing machine, then persuaded her to kill herself when she cracked under the pressure.
  • Adapted Out: In contrast to the above, all of Dog's backstory was replaced with a generic sting operation in the anime. He comes off as a flatter character because of that.
  • A Death in the Limelight: Happens in all adaptations, which give the spotlight to the character that bites it by chapter's end.
  • Animal Jingoism: Despite only having the titles of their zodiac animal, each member still manages to have traits of the animal they were assigned. Boar arrives late, Rat is shifty, Ox kills just because, etc.
  • Animal Motifs: Every warrior has something that identifies them as their respective animal.
  • Anyone Can Die: It's a battle royale with only one possible victor; if they didn't die by murder, than the Beast Gem poison would have done the job. There's only a matter of who dies sooner than who.
  • Arc Number: 12. The War happens every twelve years, there are twelve participants, twelve Beast Gems to collect, and twelve hours to win it all before the poison in their bodies kills them. Even this year's host is named Duodecuplenote .
  • Badass Grandpa: Ram may be old (Boar even thinks he should be half dead by now), but he still manages to rank as one of the nation's best killers.
  • Bad People Abuse Animals: Kiyoko in the anime. She was just as into the assassin business as her sister, but she only limited killing to animals nearby her home. She didn't start killing humans until her dear sister Toshiko taught her how to show no mercy to her enemies.
  • Composite Character: Due to the narrative difference between the manga and novel, Navi gets to be the information man and thinks several other characters' thoughts.
  • Conveniently Empty Building: Invoked by the organizers of the Zodiac War. In only one day, they manged to get rid of everyone in town so the participants can have a big stadium to play in.
  • Developing Doomed Characters: As this is a battle royale tournament, inevitably characters are going to die off in the middle of their character development. Boar had the first chapter to explain her motivations, and the anime even went as far to show her entire life up to that point, but she winds up dead at the end and becomes one of Rabbit's "allies".
  • Eastern Zodiac: The main motif of the war. With the exception of Snake, even their deaths followed the standard order of the Eastern Zodiac in reverse.
  • Everyone Has A Special Move: Courtesy of their guardian signs.
  • Fan Disservice: You'd think a handsome, ripped man wearing nothing but a skimpy bunny suit would be hot, wouldn't you? Not when he's mentally unhinged with constant dilated Black Eyes of Crazy and very willing to chop people up to make "friends".
  • Foregone Conclusion: After seeing the first couple of focus characters die, it becomes easy to see that the kill order matches up almost completely with the Eastern Zodiac in reverse. So after Boar, you know it's going to be Dog, then Rooster, etc.
  • Foreshadowing: The anime's opening gives the final survivor away with a visual cue. All of the eventual dead have glowing eyes in the character montage— that is, all except Rat, who is the eventual winner.
  • Helping Hands: Corpses that are reanimated by Rabbit's ability are capable of this trope, as hacking pieces off them does not debilitate the corpse, but instead creates more pieces which can attack the foe.
  • Idiosyncratic Episode Naming:
    • The light novel and anime both feature common Japanese phrases that mention the animal that the chapter's focus was assigned.note 
    • The manga uses the names of the warriors that appear in it. note 
  • Image Song: A rap battle produced as a tie-in to the anime serves as this for the fighters, with each one having his or her own verse.
  • Legacy Character: Every fighter in the Zodiac War is this, as they all inherited their titles as warriors of a specific zodiac sign from those that fought in the Zodiac Wars before them.
  • Make a Wish: Whoever wins the War gets the chance to wish for whatever they want.
  • Nigh-Invulnerability: The jewels are invulnerable to nearly any sort of damage, with human stomach acid being the only thing that can destroy them.
  • Punny Name: All of the contestants have names based off of their Zodiac animal, even before getting their codenames. Heck, even their codenames can be pronounced differently to get new words. Given who wrote it, what did you expect?
  • Regularly Scheduled Evil: The Zodiac War happens every 12 years.
  • Spoiler Title: Due the puns the sayings in each chapter have, some of them turn into major spoilers the more you read. "Cutting a Chicken with an Ax-cleaver"note  is just the icing on the cake.
  • There Can Only Be One: Each participant has swallowed a jewel of crystallized poison (Called a Beast Gem), and they have 12 hours to kill the other eleven and obtain their jewels to get the antidote.
  • Third Line, Some Waiting: The anime turns Horse's story into this. Between the "focus" participant of the episode and Monkey and Rat's subplot, Horse's story is about as far removed from the former two as one can get. In contrast, the novel instead has all events featuring Horse be contained in his focus chapter.
  • Underestimating Badassery: The fatal flaw of a great many participants. They're so short sighted that they can't see that their opponent might have something up their sleeve.
    • Boar was so preoccupied thinking about a way to easily dispatch Rabbit that it opened up a blind spot while she was mentally preoccupied, and she dies unceremoniously when Snake's corpse grabs her from behind, giving Rabbit an opening to plant a knife in her chest.
    • Dog thought Rooster wasn't worth much physically or mentally, but he needed a distraction for Rabbit, so he dopes her up on a strength inducing poison. She immediately crushes his skull after getting the dosage.
    • Rooster thought she could fight on par with Ox due to her newly enhanced strength. He quickly stabs her through the eyes before she knew what hit her.
    • Monkey thought she could easily subdue and restrain Rabbit because the latter was not a trained fighter. She did not realize that Rabbit could use Snake's severed head as a camera to see his blind spots, and thus, Rabbit was able to stab her when she tried to get behind him to incapacitate him.
    • Sheep witnessed Tiger sitting on a bench and downing mass amounts of alcohol, causing him to view as nothing more than an incoherent drunk and the weakest of the fighters. He's forced to eat his words after she shreds him apart with her nails.
    • Horse thought that Snake's corpse could not use its abilities and weaponry, and thus decides to ignore a warning from Rat that said corpse might come to the bank he was hiding in. He meets his end when Snake's corpse, looking for Rat, torches the bank with Horse inside, causing him to suffocate from oxygen deprivation.
    • Snake dismissed Rabbit as a threat due to his bizarre behavior, and thus let his guard down around the latter when he detects Monkey planting explosives underneath the floor. When he tries to warn Dragon, it creates an opening for Rabbit to decapitate him.
  • The Verse: The series apparently shares one with an earlier Nisio story titled "The Wish I Want is Comparable to Twelve Wishes".