User blog comment:Xilinoc/Ch. 570 (I can't think of a witty title at 11 pm)/@comment-24572618-20140226225829/@comment-24153155-20140226232429

I think the part about Yachiru mentioning Kenpachi was not coming back can be read as that she is still unaware that Kenpachi did win the fight (with Unohana). She found Kenpachi's eyepatch, which symbolized that he would be going all out, most likely in a fight (chapter 524). I think that both Isane as well as Yachiru believe their Captains did not survive (am unable to recall if Yachiru knows Kenpachi was to fight Unohana). Kenpachi will definitely return at some point. Hopefully, he will then know the name of his zanpakuto, as well as a Shikai and Bankai.