The SoulTaker: Tamashii-gari  

SoulTaker, The SoulTaker～魂狩～, The SoulTaker: Tamashiigari

One night, Kyousuke Date returns home and finds his mother lying in a pool of blood with a knife wound in her chest. In her last moments, she stabs him too. After recovering quickly, he tries to understand why his mother did that, but gets caught up in a battle between two rival groups: the Hospital and the Kirihara Group. They try to force information out of Kyousuke about his twin sister Runa, despite his lack of knowledge about her existence. As they attack him, Kyousuke discovers he has the power to transform into SoulTaker, a terrifying mutant. With these new abilities, he vows to destroy both groups, find out why his mother acted that way, and safeguard Runa.