Kaigaku

It had been quite a few years since you last saw Kaigaku. Since you were little, you two used to fight and argue a lot. As you grew up, the tension grew stronger, almost to the point of hatred. The last time you saw him, you were about to engage in a battle to use your new katanas, but a demon got between you and you were able to escape. You never heard from him again. On a mission, you returned to the place where you had last seen each other, because the boss had ordered you to go after a demon that was wandering around the place. But at the top of the abandoned house where you used to live, someone spoke to you:

"You haven't changed at all since last time."