Ok so i suspect this is a bug.

Basically an enemy swordsman will first attack using disarm, which despite having 0 attack power will do full damage, then he will use a normal attack, meaning they get 2 attacks pr turn and can kill anything but those in medium armor in 1 turn.

I tried doing the same with my swordsman but first of all, i do 0 damage with disarm, and secondly, i can't use another skill afterwards, only move.

So the AI swordsman just seems to be broken.