In the world of Bleach, Aizen's Kyoka Suigetsu remains one of the most formidable Zanpakuto due to its unique power of complete hypnosis, Kanzen Saimin.After fusing with the Hogyoku during the ...

If he got Zangetsu's permission, Ichigo could use this form again, ... If Ichigo used the Final Getsuga Tensho against Aizen again, he would win. However, that doesn't seem to be an option for him.

Aizen played an integral role in the final fight of the series by managing to masquerade as Ichigo and taking a nearly fatal blow from Yhwach. This allowed the real Ichigo to end the fight.