What is he?

One almost immortal, while the other is almost at Death's door. Destiny and fate is the only thing that holds them together. Would something go horribly wrong? Or would this just be another stepping stone to this special relationship?

"It's all in my head, right Hyunjin?"
"I don't know, I don't get sick, child."
"That doesn't help!"
"Oh well then, what am I suppose to say?"
"I don't know, maybe 'You'll get better' or something along those lines!"
"Do you think I care if you don't get better?"
"Can't you like use your powers to heal me or something?"
"I'am NOT going to waste MY powers on a mere HUMAN!"
"I-..."
"Now let me go back to sleep."