Source: salutemag.com

5. The Juggernaut

I love the Juggernaut. He's easily one of the X-Men's best non-mutant foes.

Cain Marko is the adopted brother of a boy named Charles Xavier. The boys don’t get along, and Cain’s jealousy makes him mercilessly bully the younger, smarter Charles. They both eventually sign up to serve during the Korean War. Out on patrol, they venture into a cave and come across a strange gem. Cain attempts to steal it, and that causes the cave to collapse. Only Charles makes it out.

Charles assumes, "Welp, my brother's dead. It’s time to go do other stuff." He then bombs off. Meanwhile, the very much alive Cain grabs the gem, known as the Ruby of Cyttorak (why, yes, I did spell that correctly on the first try without looking), and it transforms him into the unstoppable Juggernaut. Juggernaut is an incredible physical threat, and that's what makes him so great. Anyone who fights him has to be able to think fast to have any chance of winning.

The classic Spider-Man story titled Nothing Can Stop the Juggernaut is a great example of this, but it's present in tons of X-Men stories, too.

                                            Source: nerdist.com

4. The Sentinels

For villains with no personalities, the Sentinels are pretty darn great, and not just because the X-Men once beat them by convincing them to go fight the sun.

As a whole, the Sentinels are a great example of totalitarianism in practice. They’re huge, menacing, and constantly watchful. They’re cold, unfeeling machines specifically designed to kill. There's a reason Sentinels are always connected with menacing business or governmental bodies.

For example, Project: Wideawake is deliberately meant to evoke governmental crackdowns on minority populations that include rounding people up, holding them, and segregating them from society. And it’s all done by machines with far less humanity than the people they're hurting.

I should add that the designs are just great. Although they've evolved and changed over the years, the basic aesthetic has stayed the same. They just look cool. And it’s great fun to see them destroyed. It's not an X-Men story until somebody trashes a Sentinel. And that happened again in last week’s X-Men Red.

                                             Source: marvel.com

3. Arcade

As promised, here’s the most theatrical X-Men villain.

Dear Lord, I love Arcade, a mercenary assassin who lures his targets to his evil theme park full of deathtraps to kill them. This park is called Murderworld, because comic books are the absolute best. So, if you want to have your hero get stuck in a giant pinball machine or fight evil funhouse-mirror versions of him or herself, you really gotta throw Arcade into your story.

Arcade is traditionally an X-Men villain, but he’s been re-purposed as a sort of general-purpose Marvel Universe foe. He conceives his most successful move when he’s so bored in prison that he burns his way through a copy of the Hunger Games (or Battle Royale; it's never explicitly stated which), and comes up with the idea of abducting a bunch of teenage superheroes and making them fight each other to the death. As a result, Arcade kills a good number of teens in just a short period of time.

So, uh, you probably shouldn't laugh at him.