Riddle Story of Devil, or Akuma no Riddle, is a twelve episode action yuri anime based on the manga written by Yun Kōga and illustrated by Sunao Minakata. The adaptation is directed by Keizō Kusakawa and animated by Diomedéa.
In the private girls’ school Myojo Academy is a class known as Class Black. Thirteen students enrol in the class; twelve are assassins and one is their target. The target of this particular Class Black is Haru Ichinose. One of the assassins, Tokaku Azuma, develops feelings for Haru and swears to protect her from the other assassins.
Already a flaw has become apparent. There are too many characters for equal development in a twelve-episode series. Initially Riddle Story of Devil focuses on one assassin per episode. The formula is changed up for episode six, which does mean sacrificing one assassin’s character development almost entirely.
There are also other characters beside the students of Class Black; some are more important to the plot than others. Of course, they don’t receive too much focus either.
Due to the ‘assassin of the day’ nature of Riddle Story of Devil, you are guaranteed to see Tokaku and Haru come up against an assassin in each episode. This is a good thing, as the action sequences are enjoyable to watch. Watching the assassins reveal their skills and witnessing Tokaku and Haru attempt to overcome them is definitely a high point in this anime.
When there is character development, it is actually fairly good. A prime example is the relationship between Tokaku and Haru. A few of the other assassins have relationships with each other. Due to the nature of the series, a few assassins get a lot more screentime than the others. Whenever an assassin steps up, their motivation is revealed as well. Knowing what each assassin is fighting for helps the viewer to empathise with them.
Without spoiling anything, the ending can split opinions. Some may see it as a cop-out, whereas others will appreciate it.
To conclude, Riddle Story of Devil is a fairly enjoyable anime, even with its inherent flaws. The action scenes are the highlight, and watching Tokaku’s relationship develop with Haru is enjoyable. Of course, since Tokaku and Haru are the main characters, this is inevitable.
Score: 8/10
Only twelve episodes means sacrificing some character development, but the action is certainly worth watching.
Rory Muses 
Several cynics complained that the ending ruined the show. How fickle. Just because the destination was unsatisfactory to some does not mean the whole show sucked. More consensual lip wrestling would have been appreciated though.