Board Thread:General Discussion/@comment-24815992-20140619090507/@comment-40216804-20190720152631

Timjer wrote: Well, I admit my theory has some holes in it. And it's frustrating that is was never properly answered in the manga, but it's the best explanation I've got.

Anyway, due to a quick search I just did, the best I could find was in "Do Know Always Love You", Isane flashing back to the last time she saw Yachiru (Gremmy fight) who (according to the translator) said "Finally Ken-chan can call out to me" before she dissapeared the moment Kenpachi released Nozarashi against Gremmy. You are on track now. The piece your missing in the puzzle is Gremmy's power. Which was to make imagined things real.