Board Thread:Questions and Answers/@comment-9826910-20130618064245/@comment-3042759-20130719075459

A zanpakuto and the shinigami who wields it are two halves of the same coin. When one finally accepts through jinzen or other realizations that you are the sword, you can reach your full potential. The zanpakuto starts as Asauchi, the blank template on which the shinigami imprints his soul and the power within it. Through training, one can eventually reunite sword and soul. Aizen Sosuke can bend the senses still because it is his innate power that he imprinted onto his zanpakuto Kyoka Suigetsu. The same is seen with Muramasa and Kuchiki Koga in the omake arc The Zanpakuto Rebellion. When sword and soul are separate, the sword acts as a totem to make your true powers manifest, but the connection is limited. Ichigo's power was further limited by his quincy powers holding the sword for him as a proxy, even after the time in the Dangai. All bets are off when it comes to what Ichigo's true limits are now. I suspect they will exceed his post-Dangai form by a great deal when he uses Bankai. When a Bankai is stolen, either by Muramasa's subversion or by that quincy medallion, the sword is diminished without the hand of its master on the hilt. Neither is complete without the other. The Bankai severed from its master is still enough to overwhelm that person, but cannot be focused to effectiveness against one who retains his sword in hand.