-snip-
Actually, I think he would be more of a socially awkward hermit with strict moral standards (which is how you can sum up my personality in reality, to tell the truth) who has honed his skills through meditation (If bay forum was a mountain hall thread again) than what you suggested.
It really wouldn't matter because you yourself have already set your character up as an entirely rediculous villain who gets SEVERELY depowered once he joins the party.
So sure he is a socially awkward hermit with strict moral standards... but you already cooled your way into the story, intentionally stunted until people couldn't deny it, then became a pathetic loser simply because you lost one battle and joined the party.
Anyways...we discussing Zanzetkuken? I like the "powerful boss turns into weak but tries-hard PC" idea
I know it works so well especially since Zanzetkuken keeps filling in how awsome his character is. Afterall he is a hermit (aka the dark mysterious loners) who can turn into a dragon who is stronger then everyone else and can even kill everyone with a single hit (dealing 101% of their HP in damage in every strike).
He had, while being in NPC form, the most powerful weapon and armor in all of existance!
The question is how much should we play up his fall into patheticness.
I still like the idea that you earn his ultimate weapon and armor after you beat him and he joins the party... yet no one, not even him, can equip them... So the goal is to turn them into Amazing Garbage so they are ruined just enough for him to use.