Board Thread:Questions and Answers/@comment-5303512-20191025210913/@comment-29325824-20191026170240

Yeah, Yachiru having her own powers unrelated to Nozarashi's powers is certainly a big problem in the theory. I'd suggest it's like Tenken's fire powers (Spirit, but not sword), but sadly that was non-canon to begin with. Plus, you'd think that when Nozarashi finally spoke, Kenpachi would recognize the voice as Yachiru's, and Yachiru would have noticed earler rather than during Gremmy's fight.

Xilinoc's theory does make sense, but it also can't explain why Yachiru just vanished at that moment and Kenpachi stopped caring about it afterwards (aside from a brief distress).