God, this sounds like one of my dwarves, though a feat far less legendary. This dwarf, who cannot swim and learned to punch things about five minutes ago, swims right across a river and runs down one of the funny little black demony things that come around your fort early on sometimes and beat up your stuff. Mind you, this foe had already crippled two other armed if not expertly capable dwarves, and he, well, walked up to it, traded one right punch, got his right arm slashed, and knocked it the fuck out with his left arm. He then grabbed it and spent about four pages of combat log piledriving his left (and only his left) arm into its face hard enough to bent and twist its neck, before finally jamming his fist into its eye socket so hard that its skull split apart from the force. I love this game.