The leader of a fleet of six warships that were encountered by King Oláfr on his journey to Norway. One of Oláfr's men, Kári, told the ugly Hröngviðr that he had never known worse than him and that he shall cut him into tiny pieces. Hröngviðr replied that he had harried summer and winter for thirty-three years, fighting sixty battles and always had the victory. He challenged Kári to come back the next morning.
Kári and his brother Örnúlfr returned and told the king the news. Oláfr decided to accept the challenge and a hard battle followed. Kári always felled eight or twelve men with each stroke, and when Hröngviðr saw that, he ran up to Kári and killed him. He then slew Örnúlfr with his spear. Hröngviðr told the king's men to give up. The hero Hrómundr, who was in the king's following, grabbed a club and stormed forward, taking up the king's standard, and beat the enemies to death with his club. He then gave Hröngviðr so great a blow that he bowed his head and said that in all his battles he had never taken such stroke. Hrómundr then gave him another stroke, which broke his skull, and a third, in which Hröngviðr lost his life. And that was the end of the battle.
Hröngviðr's sword was called Brynþvari, which never went blunt. His brother was Helgi the Valiant.
- Hrómundar saga Gripssonar, 1-2.