Every MCU Villain Ranked Weakest To Strongest
3. Surtur
Not much really needs to be said about Surtur. He was a Fire Demon prophesised to destroy Asgard in an event known as Ragnarok, but was defeated before reaching his full power on two separate occasions - first by Odin, then by Thor an age later.
After his second defeat, Surtur was killed and his remains hidden in the vaults of Asgard. Thor intended to keep them hidden, but upon realising there was no way to stop Hela's powers from growing, he had Loki rise Surtur from his sleep.
Surtur, given full power by the Eternal Flame, grew to Goliathan heights and destroyed both Hela and Asgard with just the swing of his sword.