In the original story, Aizen had been sealed by the spell inside his body during this final evolution, forcibly interrupting the process.
But due to the earlier accident, Urahara Kisuke's contingency measure had failed to take effect on Aizen. As a result, Aizen's sixth form, which had never appeared in the original story, emerged!
Ichigo's "Final Getsuga Tensho" had led the Hogyoku to judge that the fusion of a Zanpakuto and a Soul Reaper represented a higher level of life and dimension, so the Hogyoku had also caused Aizen to evolve in that direction.
The "Kyōka Suigetsu" in Aizen's hand had not vanished. Like Ichigo's Zangetsu, it had fused with his body and become a new source of power.
Following the naming convention of "Final Getsuga Tensho," Aizen's current state should have been called "Final Kyōka Suigetsu."
No, calling it "final" was not entirely accurate. For Ichigo, using this cheat required him to lose his Soul Reaper powers, making it a one-time thing.
But Aizen was different. The power he had gained from the Hogyoku, the power that had fused with his Zanpakuto, had no side effects whatsoever for him, and he could maintain this form indefinitely!
Ichigo's cheat was disposable, while Aizen's was permanent.
Having fused with his Zanpakuto, Aizen's body began to acquire the characteristics of a weapon ability, much like Ichigo in his "Final Getsuga Tensho" state.
Not only had his spiritual pressure grown stronger and the dimension he inhabited risen higher, but his body had also begun to become as ethereal and illusory as "Kyōka Suigetsu."
Ichigo's second "Mugetsu" had clearly struck Aizen just as before, yet this time, the Aizen it hit dispersed like ink in water. He then Teleported in front of Ichigo and slashed him with a backhand stroke.
Blood sprayed into the