User blog comment:Xilinoc/Ch. 668 - BIGGER,FASTER,STRONGER/@comment-957629-20160331154647/@comment-28861328-20160403184502

Because the spirit doesn't exist before the Shinigami imprints. Remember those faceless things at Nimaya's palace? Those were Ausauchi. Yet Yachiru remembers being an infant (before she met Kenpachi), and we see in flashbacks that she's not some faceless thing, which means, if she was a Spirit, someone already imprinted upon her and it wasn't Kenpachi, which only deepens the plot-holiness.