|Alternate Identity||Sword of Surtur|
|Powers and Abilities||Changes in size, Powerful fire blasts, Corrupts user, Possible intelligence|
Elderstahl was a powerful sword used by the fire demon Surtur. It was crafted by dwarfs. It could change in size and shoot powerful blasts of fire. It also corrupted the user by seeking out their dark side and exploiting it. The Dark Elves of Svartalfheim asked Surtur to defeat the Frost Giants of Jotunheim for them. Surtur saw this as an opportunity to take over the nine realms. He used Elderstahl and attacked them but fought Odin and Gungnir. Odin eventually killed the demon and his sword was lost. Warriors then tried to find the sword in their quest for manhood. The Jotuns feared it would be used to destroy them. Tales of Surtur's final battle were told to children in Asgard. Thor, Loki, and the Warriors Three found the sword and Thor used it to kill two Jotun sentries. Horrified at the sword, he tried to protect it from others. Brunhilde wanted the sword and Loki almost used it against her. Algrim then took the sword but was corrupted. He then used it to attack Odin and later Thor. Thor used Gungnir to stop the Dark Elf and Loki used the sword to kill Algrim. Thor then gave Elderstahl to the Frost Giants. Geirmarr wanted to use it to kill Thor but Thrym stopped him and took the sword. He then spared Thor and took the sword back to Jotunheim.
There is no known name for the Sword of Surtur/Surtr. The producers had to make up the name. It means "hellfire steel." At one point comic Surtur did wield another sword called Twilight, though this was not based off that sword.