Taskmaster, really?! Yes, really! While he may not be anywhere near as powerful as some of the other baddies listed here, this is one villain who The Avengers should wish doesn't exist even if they've only clashed with him on a handful of occasions. That's because all of the A.I.M., HYDRA, and cannon fodder level soldiers they face are trained by the villain who pockets a nice little free from the organisations that employ them. However, when he's not busy training goons, the assassin has shown himself to be a formidable threat to the team during battles with the likes of Captain America and Spider-Man. His photographic reflexes mean that Taskmaster can replicate the fighting style of anyone he faces, so while he's lacking super strength and a magic hammer, he can still take down a fairly long list of Earth's Mightiest Heroes if necessary!