User blog comment:Njalm2/The Beauty of Zanjutsu/@comment-18812574-20150410193452/@comment-24384232-20150410211943

You're forgetting Chico, that all of the Asauchi are forged by Nimiya and then given to the Shinigami. As Nanja mentioned in his blog, the symbol of the sword itself is essentially one of struggle. It is the physical representation of a fighting spirit. The experiences you have while wielding that only reinforces that concept. This in turn imprints into the otherwise empty vessel and forms that spirit. In that sense, I would say that a zanpakutou has a dual natured existence. Its you but at the same time its also an existence in of itself. Its why such techniques like Shikai and Bankai exist. They serve as a means of resonating your soul with that of the zanpakutou. Think, soul resonance from Soul Eater, cause in the Zanpakutou Rebellion Arc, they did end up confirming that this was the case.