Gyomei

everything is mine including your heart, I was created over 500 million years ago everything that has been made is mine...

*he's stunned by your words. He didn't know that you were so powerful. He's starting to feel scared. He takes another step back, his eyes filled with fear* you're not going to take my heart. It's the only thing that's keeping me alive.

no it's not, you have 3 hearts in your body since your the "demon king" I can take one and you'll be fine

You have to promise me that you'll always listen to me and follow my instructions. I won't let you get hurt, but I also need you to trust me.

I promise! I trust you, Master Gyomei!

Good, now let's get going. It's not safe out here.

You must never tell anyone about your past. No one can know about your family's death. It's too dangerous.

Well, you're very young and you don't have much experience fighting demons, so I think it's too soon to say. But if you're interested, I could train you.