Kyōka Suigetsu (Zanpakutō spirit)

Kyōka Suigetsu is the manifested Zanpakutō spirit of the former of the, and current prisoner of ,. She is, uniquely, the only Zanpakutō spirit no longer bound to an base. Due to Aizen's merging with the, and the subsequent ramifications, her former physical form has truly merged with Aizen, granting him the ability to use her abilities without calling forth a blade.