u/F7_2007

Aizen knew Kisuke before he was taken in by Yoruichi. In fact, quite some time before that.

That insinuates a lot of things that we may find out about in the h*ll arc. They might have close ties to the Royal Guard because no way they were both chilling in the Rukongai and just found out by the Shihohin family. There would also be some opposition if Kisuke was a normal person from the Rukongai. Also the fact that everything he does points towards the Soul King and he tried to replicate Tenjiro's hot springs which he should not have information about.