when you see a character is too strong (or too weak, that might happen lol) you can remove him, her from arcade.
NOTE:that won't work for survival. 1) go to select.def in data folder
not much to say about it
2) look for the char you don't want to fight in the char list
omega is cheap, so here he is
ozero, stages/cathedral2.def, order=10, music=sound/Gorudo.mp3
3) change his order from the number it was (it was 10 for omega) to a letter(i'm gonna use B, i personally don't know if it works with other letters lol)
ozero, stages/cathedral2.def, order=b, music=sound/Gorudo.mp3
4) remove special char music as it works only on arcade (it would be useless letting it there)
ozero, stages/cathedral2.def, order=b
5) save modifications (once i forgot lol)
that's all! now you won't fight him in arcade mode!