One of the sons of Guðrún by Jónakr, and brother of Hamðir and Erpr. When Guðrún learned that her daughter Svanhildr had been murdered by king Jörmunrekkr, she urged her sons to avenge their stepsister.
When they were preparing for their journey, she gave them birnies and helmets so strong that iron could not bite into them. She laid these instructions upon them: that, when they were come to King Jörmunrekkr, they should go up to him by night as he slept: Sörli and Hamdir should hew off his hands and feet, and Erpr his head. But when they were on their way, they asked Erpr what help they might expect from him, if they met King Jörmunrekkr. He answered that he would render them such aid as the hand affords the foot. They said that that help which the foot received from the hand was altogether nothing. They were so wroth with their mother that she had sent them away with angry words, and they desired so eagerly to do what would seem worst to her, that they slew Erpr, because she loved him most of all. A little later, while Sörli was walking, one of his feet slipped, and he supported himself on his hand; and he said: 'Now the hand assists the foot indeed; it were better now that Erpr were living.' Now when they came to King Jörmunrekkr by night, where he was sleeping, and hewed hands and feet off him, he awoke and called upon his men, and bade them arise. And then Hamdir spake, saying: 'The head had been off by now, if Erpr lived.' Then the henchmen rose up and attacked them, but could not overmaster them with weapons; and Jörmunrekkr called out to them to beat them with stones, and it was done. There Sörli and Hamdir fell, and now all the house and offspring of Gjúki were dead.
Bragi the Old wrote of the fall of Sörli and Hamðir in that song of praise which he composed on the legendary Norse ruler and hero Ragnarr Loðbrók:
- Once Jörmunrekkr awakened
- To an dream, 'mid the princes
- Blood-stained, while swords were swirling:
- A brawl burst in the dwelling
- Of Randvér's royal kinsman,
- When the raven-swarthy
- Brothers of Erpr took vengeance
- For all the bitter sorrows.
- The bloody dew of corpses,
- O'er the king's couch streaming,
- Fell on the floor where, severed,
- Feet and hands blood-dripping
- Were seen; in the ale-cups' fountain
- He fell headlong, gore-blended:
- On the Shield, Leaf of the Bushes
- Of Leifi's Land, 't is painted.
- There stood the shielded swordsmen,
- Steel biting not, surrounding
- The king's couch; and the brethren
- Hamdir and Sörli quickly
- To the earth were beaten
- By the prince's order,
- To the Bride of Odin
- With hard stones were battered.
- The swirling weapons' Urger
- Bade Gjúki's race be smitten
- Sore, who from life were eager
- To ravish Svanhildr's lover;
- And all pay Jónakr's offspring
- With the fair-piercing weapon,
- The render of blue birnies,
- With bitter thrusts and edges.
- I see the heroes' slaughter
- On the fair shield-rim's surface;
- Ragnarr gave me the Ship-Moon
- With many tales marked on it.
- Skáldskaparmál, 41.