Please tell me this is something from Dissidia. FF2 Emperor is bland as hell and has like three lines. Leon is better (you can at least see hints of an anti-hero that a game with a non-terrible story might have been able to execute well) but still highly unsatisfying.
Ok, I guess Dissidia has influenced my opinion on him, but I played FF2 first and already formed my opinion on him back then.
The deal about the Emperor is that he gets **** done. No tragic pasts or hidden depth, just some insane bastard who literally sold his soul to Satan and enjoys serial killing towns for the lulz. And he completely destroys the "evil emperor's lieutenant is the real villain" cliche - before it even existed. That was what cemented him as a badass villain to me. Usurping GOD in the "sequel" is also quite the notable achievement.