Tbh i think Revan wins because he's a master at manipulating, just think, he managed to manipulate everyone he knows
he got himself a biggg army and owned the republic. he would be to sion " dude just dont be immortal and ill give you cookies..." and then sion like" Yummm, i like cookies." and then when he's baking the cookies sion comes up behind him and tried to back stab him and then revan pops out and smacks him round the head with an oven tray... The end.