I think I'll go the opposite route of Yuki where this guy's pretty old and has reached the peak of his powers through hard work and determination instead of just being born with them.

He's an Augmenter who has meditated with Tibetan monks, playing off the idea that monks do these amazing things because they are exceptional channelers. He's going to look young for his age because of reaching the peak in Augmenting, and the monastic idea of "perfection of the body"