User blog comment:Xilinoc/Ch. 680 - THE END 2/@comment-25383931-20160630154739/@comment-25192437-20160701145950

And if Aizen bonds with the Hogyoku again - assuming he was separated from it in the first place? Each time Aizen came close to defeat during the Deicide arc the Hogyoku transformed him into a more powerful form, so if he were to fight Yhwach with constantly-evolving and increasing abilities he would eventually metamorphose into something surpassing even his "final" Hollow-like form.