He's crazy, plain and simple. At least he'd have to be to wonder these lands seeking a fight round every corner, right? I mean who would wait till they drank half a keg before they decided the 3 guys at the other table had impugned his honor? Apprently a KegHammer would, especially Mordin. A decent fellow when he's sober, Mordin enjoys rough humor and blasting out dwarven ballads when he's had the benefits of Ale.
Though there are times you'd be ahrd pressed to find it, Mordin has a soft side, and seeing the effects of the alte unplerasantness on sandpoint, he had to help. His strong back and dwarven stubborness have proved useful in the town's rebuilding effort.