Can't remember title of movie.

Okay, it was probably made in the 2000's.

I remember the movie focused on a Homeless man in search of someone (perhaps his brother) and in his head he keeps having battles with this God (in which the man is honing his abilities). After his final fight with the god in his head he has a final battle with a man who uses some kind of poison or drug to his advantage (but eventually loses).

The God-like figure that appears in his dreams/visions that he spars with Might be the Monkey King from Journey to the West, but then again it could just be a god. I'm also not speaking of The Forbidden Kingdom or whatever the Jet Li/Jackie Chan movie was.