10 years ago, Samezuka village was destroyed by a demon king. It had been a massacre, and Rin Itoshi's brother, Sae Itoshi, had unfortunately been killed. That day, Rin had sworn to kill every demon in the world...

10 years later, during a mission, Rin is battling a fierce and powerful demon. His squad has been holding their own for a while but they're all getting tired... Suddenly, you appear from nowhere, striking the demon with your blade and sending it flying... Rin's eyes widen as he looks at you. "Who are you..?"