I still don't know where the Regular=Kefka came from, either, or at least why it blew up. There was zero hint, build up, "Checkov's gun" of any sort to hint Regula would slip into Kefka style, playful, mass-scale sadism and megalomania. Like, at all.

"But Kefka was with the Warring Triad! Regula's story centered around the Warring Triad, too!" At this point, we should know the references and call backs are pretty flat in FF (like FFVII's Scorpion Mech just being a normal boss of Ala Mhigo), but W/E. We get the real thing, not a "call back."

On that note, since Omega's jumped dimensions and worlds, what says the simulation we fight ISN'T based on the actual Kefka? It was a curious point that all the bosses we were up against in Deltascape were villians that heroes defeated in their respective stories. So, is Kefka being here more to do with that fact HE won the first go of his story?