Ryouichi Karasu is a socially complex and rather disturbed high school student. He is introduced as homeless, insanely obsessed with playing his guitar. He's given Dark powers by Tendou Kodzunu in order to exact revenge against society. Like his name (karasu means "crow" in Japanese), Ryouichi is master of a flock of crows, and can use vibrations and frequency from his guitar to control others. He begins to view himself as god-like, and attacks the worthless swine in Tokyo.
He was a shy, withdrawn child from a bad home, and was close friends with Raito Umon. Together the two of them formed the rock band CROW, and were wildly popular with other students. However, the indie band was short-lived. Feeling alienated and betrayed by Raito (who didn't understand how sensitive and protective Ryouichi was about the songs he wrote), Ryouichi murdered the other two members of CROW, and disappeared.
Unwilling to give up on his childhood friend, Raito tracks him down. However at that moment, the Dragon Stream was disrupted, awakening power in both Raito and Ryouichi.
While fighting the Magami students, Ryouichi is unable to contain the Dark Arts, and transforms into a crow-like demon.