Technically, Sephiroth is the final boss of
FF7, but because it's a staged fight many consider
Safer Sephiroth to be the final boss.
Ganon at the end of LoZ: OoT was weak.
A Stalfos is harder than him.
Halo didn't need a final boss. An all-out Covenant assault would have done the trick. But nooo, Bungie had to throw in that albino... thing.