Riddle Story of Devil

""The world is full of forgiveness.""

- Haru Ichinose, Episode 1

Tokaku Azuma is a heartless teenage assassin on a mission of death. She's been sent to a prestigious boarding school to compete in an assassination game against eleven other beautiful killers. Their heinous mission: send the innocent and cheerful Haru Ichinose to an early grave. But when Tokaku finds herself strangely drawn to her intended target, she must utilize her lethal skills to keep her new friend alive -- and Haru must place her life in the ruthless, cold-blooded hands of the very woman sent to kill her.

Akuma no Riddle (悪魔のリドル, lit. Devil's Riddle), published in English as Riddle Story of Devil, is a Japanese manga series written by Yun Kōga and illustrated by Sunao Minakata, licensed in English by Seven Seas Entertainment. An anime adaptation by Diomedéa aired in Japan between April and June 2014.


 * Assassin Outclassin'
 * The Clan: There are two assassin clans which have existed since ancient times: the Kuzunoha Clan of the West and the Azuma Clan of the East. Tokaku is the heiress of the Azuma Clan,
 * Deadly Graduation: The graduation itself was perfectly lovely. Cherry blossoms, singing, the whole shebang. It was how they got to where they were in the epilogue that made it "Deadly". This conflict of interest had different endings between the anime and manga, corresponding with the different versions of Haru starring in them:
 * The Badass Damsel Ending:

""I chose the person with the worst judgment. Tokaku, your life isn't worth a damn to anybody!""
 * The Damsel in Distress Ending:
 * Death Notification: Inverted. Each assassin gets 48 hours to kill Haru once they deliver their advanced notice, and if they fail to do so within the time allotted, they are immediately expelled from Class Black.
 * Elaborate University High: Myōjō Private Academy integrates grades K through college into one major academic campus. The Grade 10 freshman year was divided into five classes: Class Blue, Class Green, Class Red, Class White and Class Yellow. The sixth and final class, Class Black, was only opened to enrollment at irregular intervals ranging anywhere from dozens of years apart to back-to-back.
 * Evil Parents Want Good Kids:
 * Hero Secret Service: Tokaku is single-handedly serving this role for Haru against eleven other trained assassins.
 * Idiosyncratic Episode Naming: The episode titles are riddles texted to Tokaku by her psychology teacher from Private Academy 17, Kaiba.
 * In Love with the Mark: Deconstructed. The basic premise of the story is Tokaku rejecting her mission and protecting the intended target from eleven other assassins, and there is plenty of chemistry between her and Haru. However, the story also points out the sort of bad judgment someone would have to have for this trope to even get off the ground, as well as the sort of insane skills and luck they would need to survive its implementation. As Lampshaded by Kaiba:


 * Knife Fight: Between Tokaku and Isuke, both in the Opening Theme and when she makes her attempt on Haru's life.
 * Psychological Thriller: Akuma no Riddle deconstructs what sort of personalities and circumstances would be necessary for tropes like In Love with the Mark to function and explores the psychological implications of being a Hitman with a Heart and how a teenage girl becomes a Professional Killer in the first place.
 * Pun-Based Title: The Japanese title is a pun on the Devil's Trill Sonata by Giuseppe Tartini.
 * They Changed It, Now It Sucks: YMMV on whether Akuma no Riddle was Ruined FOREVER, but as a psychological thriller (which it was marketed as!), the anime adaption took a clear downward turn in quality, if only because of Haru's Character Derailment. In the original source material, Haru was a Badass Damsel, and as one of the two main characters, her characterization has a huge impact on the plot. In the anime, her character was taken in a distinctly more Damsel in Distress direction, which required serious application of the Idiot Ball to justify without the story coming apart.
 * Twelve-Episode Anime: Plus one Beach Episode OVA starring the complete cast, bringing the total to thirteen.
 * Twenty Minutes Into the Future: There are touchscreens everywhere. Even in the shower! However, the same cannot be said of the setting from the source material, whose level of technology is only as advanced as "contemporary". And aside from Kaiba's riddle texts necessitating some form of IM technology, it has no real impact on the story.