Mercenary and manhunter
my personnal guard was 20 slaver chief... mauling everyone on horse was epic!!
also sword sister are just badass!!
mercenery inf, best for siege
and when you recruit them they are already high level!!
(yes I was a greedy marchant for the first level, then a slave seller when I had more place, then a faction loyal guy who conquier lot of place, and finally a king who have to destroy his old BIG faction.... oh and I always kill khergit first... they suck so bad at siege xD)