User blog comment:Xilinoc/Ch. 668 - BIGGER,FASTER,STRONGER/@comment-6904925-20160331151238

I say, it is something similar to Starkk and Lilynette, his Spiritual Power was so immense he separated it without knowing, and maybe Yachiru was a manifestation of his full power.

By the way, why would Salubri have against Kenpachi using Bankai?