10 Messed Up Marvel Villains You Won't Believe Exist

The Shadow King is by far the most notorious villain on this list, but given his appearances outside of comics have been limited to just a few TV shows (the beloved nineties X-Men cartoon among them), it still stands to reason that quite are yet to encounter the character. Which is also probably a good thing, as far as their nightmares are concerned.

In short, the Shadow King is so evil, he's the character that convinced Charles Xavier to found the X-Men. He was the first mutant he'd ever encountered, a powerful telepath much like himself, who did all the horrible things a telepath could do if they put their mind to it, controlling people, dominating their minds, and exploiting them for his own benefit.

Following this encounter, it was later revealed that the Shadow King was actually an ancient demonic entity that had bonded with a mutant host. The entity spans across the Marvel multiverse, recruiting telepaths in order to feed off their energy, until eventually they become one with him.

If that wasn't bad enough, Shadow King is essentially immortal. The X-Men may be able to defeat him when he adopts a physical host, but it's only a matter of time until he returns to terrorise them once again. Couple that with a terrifying design and the character's near limitless reach, and you're left with a villain only a select few in the Marvel universe could ever hope to oppose.