In Sörla þáttr, a short late 14th century narrative from a later and extended version of the Óláfs saga Tryggvasonar found in the Flateyjarbók manuscript, a figure by the name of Göndul appears and instigates the meeting of the kings Hedinn of Serkland and Hogni of Denmark and, by means of seduction and a memory-altering drought, provokes a war between the two.
It has a sequel in Sörla saga sterka, where it becomes clear that Halfdan is the father of Hogni of the Hjaðningavíg.
Like the names Heðinn (O.E. Heoden) and Hǫgni (O.E. Hagena), the legend is believed to have continental Germanic origins.
Halfdan's son Högni (of the Hjaðningavíg) fights against him but later they become allies.
Hildr, daughter of King Hǫgni, was carried off by Heðinn, son of Hjarrandi (A.S. Heorrenda).