I'm thinking this for a while now what if One was a half vampire????

and that's why he isn't affected by the vampire's energy?

Awesome, I thought the same for a while ago :D

I had my suspicions too. If he really is a half blood, then that makes him a dhampire, a vampire natural enemy. that would explain all the uneasy feeling that sometimes some of the vampire get when they near him. And being a dhampire meaning he dont have same weakness like sun and stuff too. So its highly possible if hes a dhampire