Board Thread:Watercooler/@comment-27362832-20151231220448/@comment-5358597-20160104065204

I've only watched the anime, since I haven't gotten around to the manga yet. I personally think the idea is that his power stems from him unwittingly becoming a Buddah during his training. I'm sure it's more complex than that, but he's certainly beyond mortal limitations, with energy-sensing characters seeing him with "no concievable limit" which is why I suspect that he has transcended mortality and passed into Buddhahood. He doesn't seem to fulfill the most obvious criteria, which is true enlightenment, but I think it's entirely possible and understandable based on his mannerisms and thought process that he actually is enlightened. The definition of true enlightenment is completely blurred, the fact that he is so at peace with the world, unwavering in the face of all things, and somehow wiser than all in his understanding of heroism.

That's just my theory though, the initial idea was from a joke I read on a forum that I thought actually might be a good explanation, so I've made it my head-canon.