Ryuusei Takao

Takao is a Jinki Hunter who seeks Neene's power in order to defeat the elusive Source of Infection. He is a widely discussed mass murderer, having taken dozens - perhaps hundreds - of lives since he became a Hunter two years ago. To aid him in fights against Jinki Users, he uses the captured Jinki cores of past slain users to boost his power tremendously - enough to shatter Cages with a single hit. To top it off, he is highly skilled with his katana. He is in contact with a mysterious person by the name of Julie and appears to have once been betrayed by an individual called Shiro. Even with a ruined hand, he nevertheless remained skilled enough to fight Joe, Clara, Riku and Rena all at once, only retreating when he found out his 'Time' was up. He however doesn't depart without giving riku advice about Neene. Later, it is revealed he has met Yui and accidentally wounded her while trying to protect her eventually leading to her death as the rushed to the hospital. His real name is Takao Ryuusei. (Source: Wikipedia)