Fafnir (Marvel Comics) entities is stopped when Thor agrees to go to Hel's realm willingly. Fafnir later reappears in the 2011 limited series "Avengers Prime" in the aftermath of the "Siege" storyline as, at first, an adversary then ally of Thor, Tony Stark and Steve Rogers with several legions of ogres and elves in battle against a Twilight Sword wielding Hela and her army. Fafnir was originally a normal man until transformed by the properties of a magical pool into a large dragon. Fafnir retains his intellect and speech, possesses superhuman strength and durability, and the ability to breathe fire and cast illusions.
Fafnir while cooking the heart, gained knowledge of the speech of birds and learned of Regin's impending attack from the Oðinnic (of Odin) birds' discussion and killed Regin by cutting off his head with Gram. Sigurd then ate some of Fafnir's heart and kept the remainder, which would later be given to Gudrun after their marriage. Some versions are more specific about Fáfnir's treasure hoard, mentioning the swords Ridill and Hrotti, the helm of terror and a golden coat of chainmail. Fafnir appears – as "Fafner" – in Richard Wagner's epic opera cycle "Der Ring des Nibelungen" (1848–1874), although he began