User blog comment:Xilinoc/Ch. 548 - The Thin Ice (hopefully fixed version)/@comment-6904925-20130911064808/@comment-6657474-20130912222517

There's also the distinct possibility that Ryuken Ishida will join the battle against the Wandenreich, not necessarily to aide the shimigami, but for his own reasons. Afterall it was due to Yhwach's actions that he lost both Katagiri and Masaki, the two people he loved the most, so few people really have as much motive for revenge as he does. Also there's the fact that, other than the fact he can effortlessly destroy a menos class hollow and is possibly stronger than an average captain, we really don't know much about his full combat capabilities, especially when equipped with the Spirit Armour introduced in the flashback. It would be a shame to introduce something like that and not showcase what it can do.