Sellswords are pretty good choices for this role.
Sellswords are perfect for the role! They start with higher melee and ranged skill, and higher melee and ranged defence. They tend to have average max fatigue, but they usually start with several ready-made perks and level-ups, so that they can be instantly brawny and have all their skills increased to elite levels. With that taken care of, all of their newly acquired perks (which come thick and fast, thanks to the amount of damage dealt) can be picked from the offensive tree. They can be armed with 2-3 crossbows (or, better still, Spiked Impalers), along with a greatsword and a two-handed hammer or axe and perhaps (once they’ve gone berserk) a warbrand for applying a finishing touch with those 4 extra action points (bows/impalers can achieve the same end more efficiently, but maybe a warbrand is good for grueling fights where you’re locked in melee and have already fired all your bows and need an extra hit chance and two strikes per turn to finish off a foe). You’re spoiled for choice with the offensive perks. With lethal ranged weapons in reserve that cost minimal fatigue to fire, the combination of Close-Combat Archer and Killing Frenzy guarantees greatly enhanced damage with at least one weapon. But, for those occasions when an AoE attack misses all opponents, Fast Adaptation means you can take an impaler out of your pocket and be almost guaranteed to kill/wound/repel one of the bastards (and potentially make one or two of the others shit their pants). In fact, the impaler is a pretty good defensive weapon …
