Tomokui Kanata is the previous incarnation of Rou.
Tomokui Kanata was a human with ESP powers and is the previous incarnation of Rou. He died by the hands of Kirimine Aoi, his stalker. On the night of his death he had been out drinking with a female colleague when he saw Aoi alone in the dark, after which she stabbed him with an electrified knife (Nenekaruri) and killed him.
Kanata was an ESPer who awakened his ability Absorption between his late teens and early twenties, which he used to obtain other abilities and super strength by devouring other entities. He apparently was a master in martial arts and many different combat styles before his death.