Mamiya Tomosane

Tomosane is the older brother of Takuji (real Takuji's body) and Hasaki. He took on the original Takuji's personality after Takuji's death seven years before the beginning of the story. After killing his brother, Tomosane's real personality was all but totally erased, only to resurface again 6 years later in the form of a new personality, Yuuki Tomosane. Tomosane later regains control of his body.