Huh, it reads a lot more powerful than I had in mind when my sleep-deprived mind thought it up. I'll be rewriting most of it now.

Keshigomu is designed for trapping, storing, and transporting what it erases. The condition of the blade is that it is unable to inflict any actual harm on what it pierces. I forgot to put it in the description when I posted it, but other Zanpakuto are immune to the erasure effect, only appearing in the white space if their owner is erased entirely.