He fought with the assassin and managed to cut into their thigh. He went on to attack their target while Magnus was hoisting himself onto a roof. Magnus unsheathes Jack when Otis is killed by an assassin. When Jack and Magnus are greeted by Frey, he desperately tries to attack the lord of Alfheim while Magnus restraints him. Magnus then uses Jack to heal Halfborn Gunderson. After Magnus snaps him out of it, he ties the rope Andskoti to Jack to tie up the Fenris Wolf.

When they reach Lyngvi, he desperately tried to get to Surt. When Magnus and Samirah al-Abbas get Geirrod's daughters to admit they tried to kill them, he scrambles their brains.

Before they flee Nidavellir, Jack tells Magnus that if he returns him to pendant form, he'll feel as if he did everything that Jack just did, which could cause him to pass out or die. After disarming all the attacking svartalves, Sumarbrander is given the name Jack. While running away from Eitri Junior, Magnus pulls out Sumarbrander, who he then finds out has the ability to talk. Freya tells Magnus that the sword has 'special abilities' that he will need to learn to master. When visiting Freya, Magnus learns about Sumarbrander's past with its original owner, Frey. After retrieving the sword by bargaining with the sea goddess Ran, the sword turns into a pendant with the rune of Frey on a chain. After he dispels Surt with the sword, he loses it at the bottom of the ocean after dying in the human world. Magnus comments that it didn't really look like a sword - it looked more like a lead pipe and was corroded, crusted with barnacles, and covered in mud and slime. Magnus Chase retrieves the sword from the bottom of the sea before Surt attacks him. Magnus Chase and the Gods of Asgard The Sword of Summer Sumarbrander is one of the most famous swords in Norse Mythology. Sumarbrander ended up being betrayed by its original master, although he continued to obey Skirnir.

It sunk on a Norse ship in Boston, where it was found and renewed by Magnus Chase. Frey ended up trading his sword to Skírnir, his servant, to kidnap Gerd and bring her to him. Frey fell in love with a frost giant, Gerd, who he was not allowed to marry. Sumarbrander is a magical sword, originally owned by the Vanir god Frey.

Magnus chase the sword of summer