Board Thread:General Discussion/@comment-4976518-20140808063123/@comment-5553481-20140916174915

A zanpakuto is a part of you, therefore if "you" were evil, your zanpakuto would most likely be too. I ain't going to give any sort of statistics, but there is also a possibility that the zanpakuto, being a "part" of you, could be the "good" you have been repressing, although considering that Aizen KNEW Kyoka Suigetsu's name means that his zanpakuto "allowed" him to use its power.

About Kyoka Suigetsu creating a mist etc., that was Aizen feeding other people bull, so they wouldn't suspect him of being able to control them.

About Yhwach, considering Aizen has a silver tongue (not sure if that's the right expression), he could've talked to him for a long time making Yhwach simply not notice that a lot of time has passed.