Im starting to think it possible he's his uncle. Maybe Aizen's sister was Ichigo's mother? It would explain some things
Ichigo has been refered to as a pure blood. Pehaps that purebloodedness is to do with the soul king. Maybe Aizen and Ichigo's mother were rejected because the current soul king is related to them, but is the first in line to the throne before those two, so Aizen hates the soul king for taking what he feels should be his, and he became fueled by his sister being thrown out of the soul society for one reason or another (ineptitude as a potential soul king/queen).
That might explain how he knew of ichigo's birth too.
Metal Sonic did have everything except one thing... looking as viewtiful as me! (Shot)
Yeah, I think we just assumed that Ichigo's father was a regular shinigami/captain; I'm thinking his dad was one of those people who guard the key, and the place you get to the key, or the place the key takes you, or something like that. I mean, it's just to perfect that he winds up going to where Aizen planned to make the key..... and stuff.
I'm now in what's called a long distance relationship; I live in California and she lives in the future.