Magni's Death

The death of Magni, eldest son of Thor, came at the hands of Kratos upon the frozen plain around the corpse of the giant Thamur. Though Magni was only a minor figure among the Aesir, his killing turned the wrath of Asgard upon Kratos and his son Atreus and set in motion a feud that would last for years. (God of War (2018); God of War Ragnarök)

The hunt#

Following Baldur's failed first encounter with Kratos, his nephews Magni and Modi were summoned by their grandfather Odin and ordered to aid their uncle in his hunt for Kratos and Atreus. (God of War (2018))

At Thamur's corpse, Kratos discovered the chisel of the giant buried beneath a layer of ice. To reach it he and Atreus moved Thamur's enormous fallen hammer, and its weight shattered the ice and gave them their prize. The noise drew the attention of Magni and Modi, who tracked the pair to the frozen plain, Magni remarking that the giant's hammer hadn't fallen by itself. (God of War (2018))

The killing#

Magni found his targets while battling an ogre, casting the beast aside once he had killed it and ordering Kratos and Atreus to surrender. Kratos refused, and Magni, pleased by the defiance, drew his electric broadsword and joined battle with the Spartan. After a long and grueling fight, Kratos overpowered him and drove the blade of his axe deep into Magni's skull, killing him where he stood. Horrified at the death of the brother he had believed could not die, Modi fled the field. (God of War (2018))

Aftermath#

Mimir warned that, minor god though Magni had been, his death would not go over well in Asgard, and that it was the vengeance of the Aesir that Kratos should fear. Brok said the same, that the killing would mean trouble if Thor ever learned of it. (God of War (2018))

So it proved. Thor was furious to learn of his favored firstborn son's death, and he turned his rage upon the surviving Modi, beating him within an inch of his life and branding him a coward for supposedly leaving Magni to die, wounds that would later contribute to Modi's own end. The loss also caused Magni's stepmother Sif to harbor a strong grudge against Kratos and against Atreus, whom she knew by his birth name. Odin, despite Magni having died in service to his will, showed no accountability or remorse when at last he met Kratos face to face, dismissing his fallen grandsons as "kind of useless," and even Sif observed that the two had been thrown at Odin's problems without thought for their safety. (God of War (2018); God of War Ragnarök)

Three winters later, having learned of the cruelty Thor had inflicted upon Magni and Modi, Kratos came to regret the killing as he understood the arrogance that had shaped Magni's nature, though he did not hold that abuse to be any excuse for the man Magni had become. (God of War Ragnarök)