Board Thread:General Discussion/@comment-4976518-20140808063123/@comment-28044177-20170315173905

You do realize Unohanas Bankai reflects her old Kenpachi personality of relishing fighting and the kill while her shikai reflects her desire to heal people, they are completely unrelated so its perfectly concievable for Aizens Bankai to be unrelated to his Shikai

Rule 1 of Zanpakutou: "There can never be a Bankai unrelated to it's Shikai."