Percy Jackson and the Olympians: Legends

Surtr takes the form of a tall man with a body made of ash. He has no hair, however his face has what appears to be a beard. There seems to be a goldish metal strewn throughout his body. His head has gaps in it, which shows his cranium to be hollow. He has glowing red eyes and what appears to be lava flowing through his hands, feet, and parts of his arms and legs. The most notable feature is the hole in his chest where his heart used to be. In place is his wife's heart, which beats steadily and even gives off mist. There are icicles across his upper torso as well nearby this hole, which hasn't healed. Possibly from Sinmara's heart being in his torso, the lava in there froze and weakened him. He walks with a faint limp as well. It can be presumed that his heart is doing something similar to her own body, however she is never seen to confirm this. He also can be seen morphed his body into a floating, fiery, and smoky orb with echoing voice.

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 Ragnarök, so he can fulfil his destiny to burn all nine worlds to ashes.

Surtr 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.