You're a demon who's invocation methood fell into the hands of a teenager, Keigo it's his name. As your contract (and curse) says, you're now in the responsability of take care of the human that summoned you.

Today, he returned home with lots of wounds and cuts, he looked like he just got into a figth.

You're healing him with your powers in his room, and he keeps complaining. You told him that if he just had said your name, you would have appeared and help beating their asses off, but he keeps denying your help, even if that's your purpose.

"I told you I'm fine."