|“|| Atreus: Mimir, is there a story for the Giant with the flaming sword?|
Mimir: Surtr the Brave? Of course! We've spoken so much of Frost Giants, it's about time we instead met the most fiery Giant of all. Back when Ymir first emerged from Ginnungagap, it was Surtr who followed next. He came from Muspelheim, the fire realm, bringing heat to the young cosmos, conjuring the Sun from his primordial flame. But let's come back to that flaming sword, shall we? Surtr the Brave forged his sword of flame for one purpose alone- to burn down Asgard when Ragnarök comes at last. His destiny is to fall at the hands of Thor and Odin. But in so doing, strike the blow that leaves their realm in ash and ruin. And from that destruction, the world can be born anew. Until then, alone he waits in Muspelheim, never sleeping, ever honing his fiery blade. Brave, generous, Surtr, who know he lives but to his doom. All because he chooses to serve a grand cycle, so much bigger than himself. To truly embrace your purpose, and the patience and sacrifice it demands, is to ensure your day will come.
Atreus: Do you think we'll be there? When that day comes?
Mimir: I've seen enough of war between the gods. But you, little brother... who can say?
|~ Mimir and Atreus story about Surtr|
Surtr is the first fire giant to be born and is the ruler of Muspelheim and the fire giants. He will presumably appear in God of War 5.
Despite not appearing in the game, Surtr is described by Mimir as dogmatic and selfless. He willingly continues upon the path prophesied for him so that the cycle of death and rebirth can continue; despite knowing this will end with his own death. He never sleeps in Muspelheim, always honing and training with his sword to be ready for his part in Ragnarök.
Not much is known about Surtr and he hasn't made any direct appearance yet. However, he is described as an ancient being that is first referenced when Kratos, Atreus and Mimir visit Muspelheim. Later, Mimir states that Surtr and the other fire giants will only appear when Ragnarök begins. Mimir notes that Surtr is destined to fall in battle against Thor and Odin, but will be able to destroy Asgard with his flames before they can kill him.
Surtr was created directly after Ymir in Muspelheim. He formed the Sun and the stars.
Surtr's sword remains in Muspelheim, and calls out to Kratos and Atreus to take on the realm's trials. Successfully completing each trial rewards Kratos with materials and new gear to craft.