User blog comment:Xilinoc/Ch. 672 - Son of Darkness/@comment-26091912-20160503064432/@comment-6657474-20160505224737

@ Sternritter M This would be a golden opportunity to bring Isshin and Ryuken into the fight, especially since we haven't seen Isshin's Bankai and we don't know what the Quincy Spirit Armor introduced in the flashback does (much less the full combat abilities of the two). I'm sure Kubo can makeup a way for the two of them to get there to fight (after all, he's good at making stuff up on the fly).