- "Tremble before me, Asgard! I am your reckoning!"
Surtur was the ruler of Muspelheim, prophesied to be the one to initiate Ragnarök. Surtur was successfully defeated by Odin who stole from him the source of his power, the Eternal Flame, before banishing him and his entire race to Muspelheim. After Odin went missing following the Second Dark Elf Conflict, a weakened Surtur intended to finally start Ragnarök, only to be defeated and killed by Thor. Despite this, Loki later resurrected him with the Eternal Flame and used him to defeat Hela. The fire demon then fulfilled the prophecy of Ragnarök by destroying Asgard along with Hela and himself in the process, unaware that the realm had already been evacuated.
Banished by Odin
For countless millennia, Asgardian culture has foretold of an event that would bring about the destruction of their homeworld. Known as Ragnarök, the event is destined to take place when the Fire Demon Surtur, empowered by the Eternal Flame, unleashes his rage upon Asgard and consumes it in the fire. In an attempt to prevent the fateful prophecy from being fulfilled, Odin defeated Surtur and took away the Eternal Flame, locking it in his vault beneath his palace. Surtur was left without much of his powers, along with a damaged leg and arm, in exile on the world of Muspelheim, planning his revenge for millennia.
Beginning of the End
Two years following the devastation of the Battle of Sokovia, Surtur had been informed that Thor had been searching across the Nine Realms for the Infinity Stones. Surtur then took the opportunity to take Thor as his hostage, locking him in a cage within Muspelheim. When he chose to speak with him, Surtur then had the chained up Thor dropped from his cage down before Surtur's throne.
Thor expressed his surprise at seeing Surtur was still alive, noting that Odin had seemingly killed him half a million years ago, although Surtur insisted he could not die until he had fulfilled his destiny and laid waste to Asgard. As Thor explained that he had been having dreams of this, Surtur claimed that Thor was seeing Ragnarök, but before he could continue on, Thor awkwardly swung around in his chains and asked to wait until they were back facing each other.
As Surtur continued to explain how his power would grow as big as a mountain once the Crown of Surtur had finally been reunited back with the Eternal Flame, Thor, however, noted that the flame was still locked away inside Odin's Vault where Surtur could not get near it. Surtur, however, revealed that Odin is no longer on Asgard, before insisting that Ragnarök had already begun. Upon hearing this, Thor then responded by calling Mjølnir and breaking free of his chains.
Despite his prisoner's escape, Surtur merely laughed, claiming that Thor had made a grave mistake as he sent his Fire Demons to destroy the God of Thunder. Thor was unintimidated, however, as he used his Asgardian might to easily fight back against Surtur's forces. When Thor was proving himself to be a vastly stronger warrior than all of the demons, Surtur responded by using his Twilight Sword to launch flames at Thor, which he was still able to block.
Thor then proceeded to launch Mjølnir directly at Surtur several more times, knocking him back, before Thor unleashed a final blow while charged with lightning and smashed Surtur on the head. This final blow had seemingly killed Surtur as all of his power and essence was absorbed into his Crown. Thor then proceeded to make his escape while chased down by a Fire Dragon as Thor returned to Asgard and had the crown locked away deep inside Odin's Vault for safety.
- "I am Asgard's doom!"
Some time later when Thor came to reclaim Asgard from the clutches of Hela, he found it too difficult a task to defeat her alone due to her incredible strength. With the surviving population of the Asgardians disembarking from Asgard on the Statesman, Thor made a decision to actualize Ragnarök and use Surtur's power to defeat and kill Hela. Knowing the Asgardian people were out of harm's way, he ordered Loki to place Surtur's crown in the Eternal Flame, thereby finally resurrecting him.
Within moments, Surtur had regained his form and then continued growing, until he smashed through the Asgardian Palace, completely destroying it in a massive fireball as he proudly declared himself to be Asgard's final doom while he towered over the entire Realm. While both Thor and Valkyrie defeated the horrified Hela, Surtur had begun using his Twilight Sword to lay waste to Asgard, burning the streets and smashing all of the Realm's buildings apart in his fury.
With almost all of Asgard now in flames below him, Surtur prepared to thrust his blade, as was foretold in the prophecy, straight through Asgard: However, he was briefly stopped when the Hulk had jumped towards Surtur's head in an attempt to kill him. As Hulk punched at the Crown of Surtur and tried to destroy the Fire Demon, he failed to do so as Surtur managed to throw him away before Thor ordered Hulk to escape from Asgard with them before it was too late.
Moments before Surtur could complete his destiny, however, Hela rose from below the Bifrost Bridge and furiously attempted to battle against Surtur, using all her Necroswords to impale the Fire Demon. However, Surtur remained unaffected and, as foretold in the prophecy, he penetrated his blade straight through Hela and embedded it deep within Asgard. This final strike caused the foundations of Asgard to implode, finally destroying it and killing Surtur.
After Asgard's destruction, Surtur still fulfilled the prophecy of his demise. Thor, Loki, and the remaining Asgardians watched as Asgard burned and the remnants scattered into the void. Drifting through space with Thor to lead them, the new King of Asgard resolved to take the surviving Asgardian population to Earth.
Surtur was a sinister, cold, emotionless, remorseless and diabolical individual who would not hesitate to kill anyone who stood in his way, be it friend or foe. He is cruel and remorseless. He was the ultimate personification of destruction; he had used his mighty powers against his enemies, and had no fear to destroy everything in his path, indicating the fact that Ragnarök must happen and that only he can ensure it happens.
He seems to be only and completely committed to his destiny to bring forth Ragnarök by destroying Asgard. In fact, he is so committed to his destiny that, when it came time to initiate Ragnarök, he didn't even take time to notice that there were no people on Asgard. He even proved to be suicidal as he was willing to forsake his own life in order to destroy Asgard.
He also appears to have a very serious, no nonsense mindset, being visibly annoyed when Thor refused to take him seriously during their first encounter.
Powers and Abilities
Fire Demon Physiology: Surtur was one of the most powerful beings in the Nine Realms and the cosmos, powerful enough to challenge and almost overpower Thor even in a weakened and battered form; however in his limping, weakened state he eventually proved to be weak enough for the Asgardian Prince to defeat him using superior skill. Upon being resurrected by the Eternal Flame, Surtur's powers were immeasurably increased, with him single-handedly bringing Ragnarök to Asgard and destroying the incredibly powerful Hela herself fairly easily. He was even deemed capable of destroying the Space Stone alongside Asgard, had Loki not retrieved it. This makes him one of the most powerful beings in the Nine Realms and the cosmos, with Odin being the only confirmed being to surpass his might.
- Fire Manipulation: As a Fire Demon, Surtur can generate massive waves of fiery energy from his Twilight Sword to engulf his targets in flames. This fire was strong enough that in his weakened state, he was able to force Thor using his hammer back and make him struggle. Upon reaching his full might, Surtur's flames could engulf the whole of Asgard itself.
- Superhuman Strength: Even while weakened, Surtur was still strong enough to challenge Thor. After being restored to his true form from the Eternal Flame, Surtur regained full strength and was tremendously increased to incalculable superhuman levels, to the point that he effortlessly swatted away a leaping Hulk, and even fairly quickly destroyed Hela herself who stalemated both a full powered Thor and Valkyrie. However, Surtur is notably not as strong as Odin even in his true form, as the latter was successfully able to defeat him and take away his Eternal Flame.
- Superhuman Durability: Surtur's weakened level of durability is already great enough to withstand blows from Thor using Mjølnir, taking a full-power electric charged hammer blow to the head to kill him, but after being revived from the Eternal Flame, he became practically invulnerable, only slightly turning from Hulk's leaping blow, and being barely affected by Hela piercing him with many over sized blades. However, he, despite his true form, is still vulnerable to beings of superior power like Odin, who defeated him so grievously that Surtur remained in a battered and limping state for approximately five thousand years.
- Longevity: Surtur is effectively ageless, as his body does not age, which has allowed him to live for thousands of years.
- Expert Swordsman: Surtur is skilled at utilizing his massive flaming Twilight Sword, using it to swiftly slice apart Asgardian palaces, and to destroy Hela.
- Twilight Sword: A large, burning blade seemingly made up of fire. It can shoot flames to engulf any enemy and grows with Surtur after he had been revived. It's tremendously strong, enough so to destroy Asgard entirely when Surtur brought about Ragnarök by plunging his blade into the ground, shattering Asgard and everything on it, killing Hela in one strike, something Thor's hammer was incapable of doing.
- Crown of Surtur: A burning crown that holds Surtur's being. When removed, it turns a dull black/grayish color and Surtur's body disappears. It is also Surtur's source of power. When combined with the Eternal Flame, Surtur becomes powerful enough to swiftly destroy a realm as powerful as Asgard.
- Eternal Flame: The Eternal Flame is an ever-burning fire which was originally kept in Odin's Vault. After Hela uses it to revive her old warriors and wolf, Fenris, it was ultimately used by Loki to revive Surtur and bring about Ragnarök. By placing the Crown of Surtur in the Eternal Flame, the fire giant was able to destroy Asgard completely with his overwhelming power.
- Surtur is based on the Norse mythological figure Surtr. In the comics, he is a recurring foe of Thor and is responsible for the destruction of the Korbinites' homeworld when creating his Twilight Sword.