I was just thinking how interesting would it be if Yhwach released Soya Azashiro the 8th Kenpachi from prison. For those of you don't know, Soya Azashiro was the main character of Bleach: Spirits Are Forever With You who ended up causing a revolt in the Soul Society, he was so dangerous I heard they sent the Royal Guard to deal with him. Also I a heard he was Aizen cellmate.
I know this could very farfetched, but I was thinking just how cool that might be if that happens, have Kenpachi fight another Kenpachi.