Fenrir: the wolf whose soul Atreus carried in his knife

Fenrir was the old and ailing wolf kept by Kratos and Atreus. When he died, Atreus unknowingly cast a spell that drew the wolf's soul into his knife, and that soul was later transplanted into the body of Garm, the hound who tore holes between the realms, resurrecting Fenrir as a giant wolf who aided them through the events of Ragnarök. (God of War Ragnarök)

The wolf at the cabin#

During the long winter of Fimbulwinter, Kratos and Atreus took in Fenrir, along with the wolves Speki and Svanna, and the boy grew deeply fond of him. Fenrir was already old, and his age left him in failing health. Atreus believed that with enough care he would recover, but the wolf only worsened. In the end Fenrir died in Atreus' lap as the boy did his best to comfort him, never realizing that in those final moments he was drawing the wolf's soul into his own knife. Grief-stricken, Atreus buried him in the woods. (God of War Ragnarök)

The soul in the knife#

While the two were together in Ironwood, Angrboda sensed that Fenrir's soul rested within Atreus' knife, something the boy had no knowledge of. Despite his questions, she felt it best not to tell him whose soul it was, saying that he would come to understand it in time. (God of War Ragnarök)

Reborn in Helheim#

Fenrir came back in Helheim. There Kratos and Atreus faced Garm, a soulless and seemingly unkillable hound that could tear holes in the fabric of the realms. Remembering what Angrboda had taught him about souls, and how he had once placed a giant's soul into the body of a snake, Atreus drove his knife, which carried Fenrir's soul, into Garm's head. The wolf fled in pain and confusion until Kratos and Atreus found him whimpering in a cave. Atreus had hoped the soul would only temper Garm's destructive nature, but to his surprise Fenrir's gentle soul overtook the body entirely. Recognizing the wolf by the color of his eyes, Atreus called his name, and Fenrir emerged to lick the boy's face and obey Kratos' command to sit. He at once revealed his new power to tear a rift in the realms, opening a way back to Midgard. Atreus soon entrusted his care to Angrboda, better suited to handle the now-giant wolf. (God of War Ragnarök)

Ally in Ragnarök#

During Ragnarök, Fenrir carried Angrboda into battle, scattering Odin's forces and destroying the dwarven-built war machines, and was seen tearing apart and devouring a dragon that blocked Kratos and Atreus' path. When the new Valkyrie queen Gna swept in to attack Angrboda, Fenrir opened a rift and carried Gna away through it. He returned with Angrboda to rescue Kratos and his allies as the fire giant Surtr prepared to bring down Asgard. In the days after, he was seen at rest in Jötunheim in Angrboda's company. (God of War Ragnarök)

A giant reborn#

As a giant Hel-hound reborn, Fenrir was among the most powerful beings in the realms. He inherited Garm's vast strength, enough to wreck Odin's war machines and kill a dragon, along with his great durability and his power to tear rifts between the realms and travel instantly from one to the next. He carried the usual loyalty and intelligence of a dog, obeying commands with ease, though he mastered the rift-creation power with no training at all. His original grave could still be found in the woods of Midgard, and in the days after Ragnarök it bloomed with a bed of flowers. (God of War Ragnarök)