9. Surtur
Surtur is a character who was rumoured to be the Thanos-esq mastermind behind the evil plot in the upcoming Thor: The Dark World - but that doesn't look as if it's going to be the case now. He is the ruler of one of the nine realms the fiery demon realm known as Muspelheim and is an enormously powerful fire elemental whose powers include incalculable super-strength, incredible durability, massive amounts of mystical/magical power, immortality and the ability to wield Twilight, the sword of doom, a weapon that is fully capable of destroying galaxies. Surtur could indeed be introduced in a movie serving the same role that Thanos served in the Avengers movie as the massively powerful entity who is masterminding the events of the respective film, only to find himself having to get his hands dirty in combat in later movies after the inevitable failure of his henchmen. It would require someone like Odin to step in to prevent him taking over the universe, because the likes of the Avengers simply aren't up to the job. One thing is for sure though - if Surtur does ever appear in live action in the Marvel Cinematic Universe, he will look absolutely phenomenal using modern CGI and the viewing audience would go crazy for him.