The Battle

In the base level of Central Underground Prison, Muken, Kenpachi Zaraki fought the first generation of "Kenpachi", Retsu Unohana, also known as Yachiru Unohana. During which the two recalled their first fight in Rukon. Unohana saw a hidden truth from the power of delighted Kenpachi. Ichigo and Renji went to Hooden. The one waiting for them there, Ōetsu Nimaiya, is said to be "God of the Sword".