Inversion Impulse

S1 E1: Shiki Tohno sustains a life threatening injury as a child and is unable to remember things well before the accident. Due to the accident he was sent away to live with another relative. His sister has him move back in with the family once their Father dies. The day he moves back home he decapitates a woman with the stab of his knife in a moment of insanity. The woman suddenly shows back up alive and asks him to be her boyguard. Shiki accepts and begins to find out what happened in his past.