Diabolo (ディアボロ) is a Japanese manga series by Kaoru Ohashi and her sister Kei Kusunoki.
Teens who have made a pact with the Devil begin to go crazy at age 17, often manifesting in acts of brutality and homicide, and upon turning 18 reach a point of no return to their original selves.
The main characters, Ren and Rai, use their own Devil-given powers to stop them while searching for their cousin Mio, saving other teenagers from their pacts, and racing against their approaching 18th birthdays.
Diabolo was written and illustrated by twin sisters Kei Kusunoki and Kaoru Ohashi, and 3 volumes were published by Shueisha from 2001 to 2003.
[3] In Manga:The Complete Guide Jason Thompson described the "visuals and action scenes are weak".