Board Thread:Questions and Answers/@comment-46731117-20200826115351/@comment-46731117-20200826120435

Timjer wrote: Considering Shinigami are merely regular Souls with high spiritual power who's powers come from being given an (artificially created) Asauchi, I think that, in theory, any spiritual beings should be able to imprint upon an Asauchi. From Fullbringers, to Quincy, to Arrancar.

The only reason that likely never happens is because the existing Asauchi are under strict control of the Gotei 13, and Nimaiya is the only one who knows how to make them anyway.

This whole idea stems from the fact that Kenpachi took an Asauchi off a dead Shinigami or student(I can't remember) and made his own Zanpakutō. At the same time, many low ranking Shinigami still just use an Asauchi. So what if, a Fullbringer or even a High Spec Human discovered a dying Low Rank Shinigami and took their Asauchi. As far as I can tell, I haven't been able to find what happens to the corpse of a Shinigami in the World of thr Living so I don't even know if it would be possible to take one off them but this is just a theory.