|“||The sword will be mine, boy. You cannot change fate.||”|
–Surt to Magnus during their fight on Longfellow Bridge in, The Sword of Summer.
Surt came to existence by the flames of Muspellheim, in the primordial times before the creation of the universe. He stayed at his domains while Odin, Vil, and Vê killed Ymir to create Midgard and the others worlds. He stays there until the day of the Ragnarök, when he'll command an entire army of fire giants to invade Asgard and fight with the gods.
Surt tries to kill Magnus Chase and take his sword, Sumarbrander. When Blitz and Hearth come to distract Surt so Magnus can run, Surt counters with a fire blast that knocks out Hearth. Magnus then decides to fight Surt himself. Magnus hits him, but he throws him away, Magnus charges back and cuts his they and severs his nose. Surt then throws a ball of molten asphalt at Magnus, hitting his torso. Magnus charges at Surt and knocks him off the bridge. The Black One tries to fight Magnus off, before they hit the river. The two hit it, with Magnus dying and Surt being forced back into Muspellheim. Surt desires to engulf the nine worlds in flame which unfortunately will happen at Ragnarok and is also destined to kill the god Frey Magnus' father with Frey's own former sword, Sumarbrander or Jack.
He has complete power of the fire Giants and Muspelheim. Surt urgently wants to start Ragnarok as seen in the Sword of Summer and wants to take possession of Sumarbrander for three reasons: starting Ragnarok by freeing Fenris Wolf, for his on personal power growth and benefit and to wreak havoc across the nine worlds and to have it ready to slay Frey at Ragnarok Because Frey's warmth, light, growth and vitality is the only thing stopping Surt engulfing the nine worlds in flame already, that is why Surt wants to kill and resents Frey so much. Surt is also destined to kill Frey so there really is no avoiding it.
Later, when Magnus, Samirah al-Abbas, Hearthstone, and Blitzen go to re-bind the wolf Fenris, Surt appears with an army of fire-giants and fights Gunilla and the other two Valkyrie, Irene and Margaret, killing them. After re-binding the wolf Fenris, Magnus sends Surt back to Muspellheim using Jack.
Surt was mentioned by Hrym and Loki. They reveal that due to favorable tax laws, Naglfar is registered in Muspellheim and therefore Surt is the technical owner of the ship. The two say he is forced to break up disagreement between them but the fire giant was not in Niflheim.
I Play with Fire
While recruiting minor gods for post-Ragnarok reconstruction, he is being watched by Alex Fierro who is trying to sabotage his recruitment. When it looks like the gods have doubts about him, he summons his fire sword to strike fear in them. Just then he is attacked by the child of Loki and has his nose cut off again. Meanwhile backup for Alex arrives and Surt is hogtied.
Surt is a sinister, cruel, remorseless and diabolical individual, to the point that he threatened to kill a group of innocent mortals, if Magnus didn't give Sumarbrander to him. He is only interested in the start of the Ragnarok, so he can fulfil his destiny to burn all nine worlds to ashes.
Magnus describes Surt in The Sword of Summer as a human-sized dark man in a dark suit, with his skin being "the purest most beautiful shade of black [he'd] ever seen", blacker than squid ink at midnight. His clothes are the same color, and consist of a well-tailored jacket and slacks, a crisp dress shirt and tie—all seemingly cut from the fabric of a neutron star. In battle, Surt wears a trim-cut three-piece suit of chain mail, a tie and a shirt that appear to be woven from flame. Surt's chiseled face is "inhumanly handsome", and resembles obsidian, while Surt's long black hair is combed back in "an immaculate oil slick", and the pupils of his eyes glow red-hot, like tiny rings of lava. As a result, Magnus decides that Surt looks like a very stylish and well-dressed Satan. Surt's voice is described as deep and resonant, with his accent vaguely German or Scandinavian. He wields a fearsome curved sword made entire of white-hot flames. When wounded, Surt's sizzling blood glows like magma.
During his first encounter with the son of Frey his nose was cut off, however it was starting to grow back by the time of I Play with Fire until Alex Fierro cuts it off again.
Being one of the first beings to came into existence, as well as the supreme ruler of Muspellheim, Surt is one of the most powerful and feared beings in the nine worlds, his power is so great, he is fated to burn all creation to ashes during the Ragnarok.
- Prowess in Battle: Surt is an extremely formidable master at combat, and is destined to command the forces of evil during Ragnarök. In The Sword of Summer, Surt held his own against three highly skilled Valkyries at once, (one of them Gunilla, who had 5 centuries of combat experience), eventually defeating and killing all of them in the process.
- Pyrokinesis: As the ruler of the Fire Giants of Muspellheim, Surt can generate vast amounts of heat and fire at will. He is destined to unleash his full power at the very end of Ragnarök, burning the Nine Worlds with his flames.
- Heat Generation: Surt can make the air around him "ripple with heat", to the point that he can walk straight through a car, melting a path through it "like a blowtorch through wax." He also made the paved ground bubble around him.
- Firestorm: When Blitzen and Hearthstone enrage him, Surt causes flames to swirl around him in a spiraling firestorm, melting cars to slag heaps, liquefying the asphalt, and popping rivets from the bridge like champagne corks.
- Fire Sword Summoning: Surt can summon his curved flaming sword at will. However, his blade dissipates when he temporarily loses concentration, like when Sumarbrander unexpectedly wounds him.
- Fire Immunity: Surt is completely immune to any amount of fire and heat.
- Thermokinesis (limited to heat): Surt has the ability to manipulate temperature to make it hotter.
- Enhanced Strength: As a Fire Giant, Surt has considerable superhuman strength, being able to back-hand both Hearthstone and Blitzen with ease, and punch Magnus hard enough to make the latter vomit and temporarily lose consciousness.
- During the events of Ragnarök, Surt is destined to kill Magnus' father Frey with Sumarbrander, and then use his full powers to burn Asgard and the other realms.
- Surt is known to have caused the Great Chicago Fire.
- He is the inspiration for the Balrog from "The Lord of the Rings" series by J. R. R. Tolkien.
- Surt is technically Ymir and Audumbla's brother, according to the Eddas. The three was the first beings to emerge from the two primordial realms, Muspelheim and Niflheim. Surt was created by the fire of Muspel.
- This makes Surt the oldest creature still alive in Magnus Chase series.
- His Greek equivalent is Typhon.
- His Egyptian equivalent is Set based on their black/red hues and destructive storms (sand and fire).