This is probably the strangest tread I've ever seen... and Omega Weapon doesn't have any "ultimate weapon". :rolleyes2

ULTIMA Weapon wears a sword that's also called "Ultima Weapon" but Omega Weapon have no "weapon" at all. Anyway... Ultima Weapon would kick Sephiroths ass and since Sephiroth don't give a damn in Omegas attack pattern, Omega would would also kick Sephs ass. Ultima Weapon > Omega Weapon > Sephiroth.