A heroic warrior who is not what he seems to be.
A blessing can also be a curse - and the last thing the world needs is an Orcish confidence trickster with an enhanced intellect and a penchant for storybooks.
A great warrior, cursed with an eternal life and a dark companion.
Believable magic, like ordinary physicis, operates according to some invariable laws that always result in some kind of cost or "bounce back". The grater the magic, the more it should cost the character physically, emotionally, and spiritually.