Devil's Riddle is an AU of Akuma no Riddle written by Mercuriesandrandomness in which every single pair of roommates switches backstories but keeps the same personality.
Or, in which Haru Ichinose transfers into Class Black to kill Tokaku Azuma, only to fall in love with her.
This work contains examples of:
- Adaptational Heroism: Hitsugi's Yandere and Fake Cutie tendencies have been removed, leaving her as a Token Mini-Moe Nice Girl.
- Adaptational Villainy: Kaiba goes from an Eccentric Mentor Jerk with a Heart of Gold to the creepy Big Bad.
- A Death in the Limelight: Almost every chapter focuses on one of the girls and her motivations for killing, only for said character to die at the end.
- Alternate Universe: In which each roommate pair switches backstories.
- Bittersweet Ending: Tokaku and Haru are able to graduate from Class Black and live normally, but everyone else dies.
- Composite Character: Kaiba is a composite of himself, Mizorogi, Nio, and Yuri.
- Control Freak: Hanabusa is one.
- Dark and Troubled Past: Like in canon, pretty much everyone has one. The basis of the story is swapping all of the girls' backstories.
- Death by Adaptation: Everyone except for Tokaku and Haru
- Death Seeker: Tokaku, Kouko, and Chitaru.
- Expy: Shiena is one of Touko Fukawa
- Grew Beyond Their Programming: Shinya was originally programmed to be an Ax-Crazy murderer with no morality. Then she gained sentience and realized that what she was doing was wrong.
- Jekyll & Hyde: Mahiru and Shinya, like in canon, as well as Shiena's personalities. (One is a Playful Hacker Cute Bookworm and the other is an Ax-Crazy Serial Killer).
- Last-Name Basis: Everyone calls Haru "Ichinose" except for Tokaku.
- Mayfly–December Romance: Kouko was in one.
- My God, What Have I Done?: Shiena after attempting to kill Tokaku, Hitsugi after killing Chitaru, and Mahiru in her backstory after realizing that murder is wrong.
- Obliviously Evil: Shinya has no idea that being an Ax-Crazy murderer is wrong, as she was programmed to be one.
- The Power of Hate: Isuke hates pretty much everything about her life, and uses said hatred as her motivation for killing Tokaku.
- Rape as Backstory: Hanabusa, who snaps, kills her rapist, and becomes a Control Freak that desires to be the strongest of them all.
- Revenge: Otoya's motive for attempting to kill Tokaku.
- Ridiculously Human Robot: Mahiru is one.
- Self-Made Orphan: Shiena is one.
- Split Personality: Mahiru, like in canon. Shiena also has one.
- Suicide by Cop: The only reason Kouko tries to kill Tokaku is so Haru can kill her. Also, Chitaru spends most of her time in the story trying to get Hitsugi to kill her.
- The Stations of the Canon: All of the girls attempt to kill Tokaku in the same order they do in canon.
- Together in Death: Kouko and her husband, as well as Chitaru and Hitsugi.
- Token Good Teammate: Besides Tokaku, Hitsugi is the only one of the girls who isn't an assassin and is only in Class Black because she got lost and Chitaru took her there.
- The Unfought: Haru never fights either Chitaru or Hitsugi, as the latter kills the former onstage before killing herself.
