Hrun, known as "Hrun the Barbarian", was a hero. He stole the sword Kring, and assisted Rincewind and Twoflower during their adventures, joining them during an escapade in the Temple of Bel-Shamharoth.
Upon nearing the Wyrmberg of the Dragonriders, he is captured by the curvaceous Liessa Wyrmbidder and her dragon riders. Liessa's plan was to use Hrun to wrest the rulership of the Wyrmberg from her rival brothers and then become queen, Hrun's payment being her hand in marriage. Hrun agrees to the plan and successfully defeats Liessa's brothers with his bare hands, but he refuses to kill them as they are unconscious. Killing unconscious people would have been damaging to his reputation. Liessa agrees to resort to banishing her brothers. In a scene unusually erotic for a Discworld book, Liessa strips naked before Hrun to see if his desire for her will be strong enough for their relationship to work. Before he can accept the "proposal," Rincewind and Twoflower riding upon Twoflower's conjured dragon Ninereeds, snatch up Hrun in a rescue attempt and fly away with him. Hrun is extremely displeased at the event, having been denied both lordship and intimate contact with Liessa through their actions. But Hrun does not need to be angry for long: when Twoflower faints, his dragon, having existed only through his willpower, disappears, causing all three passengers to fall through the air. Liessa catches Hrun on her own dragon, and the couple share a passionate kiss.
It is mentioned in Interesting Times that he became a Sargeant of the Watch in an unnamed city, presumably meaning that he and Liessa broke up.