His father was slain by his uncle, the Norwegian king, Svipdagr. After the incident, his uncle installed him as the puppet king of the Danes. However, his half-brother, Hading refused the offer and entered exile, later he returned and retook his father's kingdom, but lack of mentions of Guthorm implies that his half-brother died before his return.[1]
GUTHORM and HADDING, the son of Gram (Groa being the mother of the first and Signe of the second), were sent over to Sweden in a ship by their foster-father, Brage (Swipdag being now master of Denmark), and put in charge of the giants Wagnhofde and Hafle, for guard as well as rearing.
Swipdag, now that he had slain Gram, was enriched with the realms of Denmark and Sweden; and because of the frequent importunities of his wife he brought back from banishment her brother Guthorm, upon his promising tribute, and made him ruler of the Danes. But Hadding preferred to avenge his father rather than take a boon from his foe.
