Come on don't spoil the fun! Didn't Canderous Ordo fight some Vong reconnaissance fleet during the Mandalorian Wars? I remember him mention something like that in KOTOR. By the way, Blackhole (Cronal) could also serve as a main villain. He was in contact with Jerec (Sariss was his daughter), he served the Emperor during Operation Shadow Hand (he captured Mara) and he probably gave Carnor Jax a platoon of Shadowtroopers.