2 soldiers with 200+ armor and greatswords or warbrands to kill the bulk of the skeletons in rounds 1-5 with AOE attacks (they absolutely need reach advantage and 30+ melee def. otherwise they will get killed very fast)
I’ve seen mercs with ~300 head and body armour (and the Battle Forged perk) and very high melee skill (and the Berserk perk), plus high hit points and resolve in case of hits, scythe through skeleton hordes with only a few scratches despite having barely any melee defence.
