User blog comment:Theraven22/bankai's that should be revealed/@comment-1774413-20100330194647

Aizen was a captain, and you have to have a bankai to be a captain (except for zaraki's case where he killed his captain, but aizen never killed his). however he couldve used his shikai ability to make it look like he has a bankai..... but seeing as how his whole ideal is about gaining new hieghts of power, im guessing hes already achieved bankai.