It is said in the end section of Helgakviða Hundingsbana II, a poem of the Poetic Edda, that the hero Helgi Hundingsbane and his lover Sigrún were reincarnated as Helgi Haddingjaskati and the valkyrie Kára, Halfdan's daughter, who were the protagonists of the Káruljóð.
Káruljóð is lost, but a part of the adventures of Helgi and Kára are held to survive in the legendary saga Hrómundar saga Gripssonar. In this legend, Helgi Haddingjaskati is the champion of two Swedish kings named Haldingr. Helgi fights against the protagonist of the saga, who is named Hrómundr, but Helgi is aided in the battle by his lover Kára's magic. During the battle, she is in the shape of a swan, but by mistake Helgi hurts the swan with his sword and is no longer protected by her magic. He is then killed by Hrómundr.
- The Hasdingi were a royal clan of the Vandals.
- Hilda Roderick Ellis, The Road to Hel: A Study of the Conception of the Dead in Old Norse Literature, Cambridge: Cambridge University, 1943, repr. New York: Greenwood, 1968, OCLC 311911348, p. 139.
- The article Hrómundar saga Gripsonar in Nordisk familjebok (1909).
- Henry Adams Bellows' commentary in his translation of Helgakviða Hundingsbana II (1936), at Sacred Texts.
- Skálskaparmál at Norrøne Tekster og Kvad, Norway.
- Translation by Arthur Gilchrist Brodeur (1916) at Cybersamurai Archived 2007-05-07 at the Wayback Machine.