[As mentioned on Plurk, my intention is to hand wave the rest of this fight. The group will get through Bizarro as long as they manage to keep their HP's up. The disturbance in the energy in and around the fight when Sephiroth finally shifts again into Safer Sephiroth draws Caius into the fight.
Eventually, he is knocked into an unconscious heap and does eventually return to his standard form.
OOC-Handwaving
Eventually, he is knocked into an unconscious heap and does eventually return to his standard form.
If you'd like some idea of the fights from canon - Youtube links below:
-Bizarro Sephiroth
-Safer Sephiroth]