It ain't always easy being the unstoppable Juggernaut. When he's not busy tearing down buildings, fighting the Xavier's School for Gifted Youngsters, Cain Marko has a lot of personal issues that he doesn't talk too much about. Wearing an unbreakable armor that's powered by a mystical ruby causes one's life to go in some awfully strange directions, and combined with Marko's clear anger problems, we can't really blame him for keeping some secrets close to the vest.

So what's going on underneath Juggernaut's armor? A lot more backstory than many may realize. Between painful family relationships, Squid-Boy friends, sex with lawyers, bar fights, and even a brief stint as one of Xavier's X-Men, Juggernaut is a much more complicated character than many realize, with a lot of emotional depth, history, and strange events that have left their mark. Here are 15 Facts You Didn't Know About Juggernaut.

15. He's Charles Xavier's Stepbrother

Fastidious comic readers have always known this, but if you primarily know about the X-Men through the movies, this might come as a surprise. Charles Xavier and Cain Marko don't just know each other through battle: they grew up together.

After the death of Xavier's father, the nuclear scientist Kurt Marko marries Xavier's mother, Sharon, and moves into the future X-Mansion. Unfortunately, the relationship between Charles and Cain goes sour pretty quickly. The problem is that despite the fact that Cain is Kurt's biological son, Kurt identifies more with Charles's introspective, intelligent nature over Cain's aggressive one. Sensing the clear favoritism, Cain begins bullying his stepbrother, which then leads to Kurt abusing Cain.

None of this is helped when Sharon is driven to alcoholism, and then dies, leaving Charles alone with the two Markos. Add in Xavier's burgeoning telepathy to the mix, and well... it wasn't the best home environment, particularly for the kid who would one day be Juggernaut.

14. He Accidentally Killed his Dad

As if all of this wasn't bad enough, it gets even messier. Strained parental relationships are a pretty common plotline in comic books, and old Juggs is no exception. The troubles between Cain and his father hit a peak one day when Cain accuses his father of playing some part in the death of Charles Xavier's father, Brian, in a (successful) bid to get Sharon's money. This erupts into a big argument, and Cain, realizing that Charles is listening outside the door, purposely tries to make a scene out of it by trashing his father's laboratory.

The lab erupts in flames, and Kurt sacrifices his life to carry both his son and stepson to safety before dying from exposure to all of the chemicals, fumes, fire, and so on. As he dies, Kurt tells Charles to not let Cain know of his mutant powers. Unfortunately, Cain hears this warning, and from that point on, his resentment of Charles only increases.

13. He's Not Really a Mutant

So here's the thing about Juggernaut. As an X-Men character, gifted with powers of super strength and invulnerability, many automatically assume that Juggernaut must be a mutant. After all, most X-Men characters are mutants. This impression is helped by the fact that other media interpretations of the X-Men, such as the movies and cartoons, have often depicted Juggernaut as a carrier of the mutant gene.

But in the comics, he isn't. Actually, Cain Marko's powers come from a mystical ruby called the Crimson Gem of Cyttorak, discovered during Cain's time in the military. When he holds the gem and reads the inscription on it, Cain is transformed into what the gem itself describes as a "human Juggernaut," vastly increasing his size, strength, and durability, while also endowing him with a mystically-powered armor -- and a helmet that is resistant to psychic attacks. Juggernaut's powers are magical in nature, rather than genetic.

12. "Cyttorak" is Part of a Pantheon of Eight Gods

Cyttorak is a lot more than just a ruby. In actuality, Cyttorak is an ancient dark god who, at some point in the distant past, was banished from the Earthly sphere and then migrated to a dimension called the Crimson Cosmos. But just as Thor is linked at the hip to Odin and Loki, Cyttorak is only one part of a bigger package.

Cyttorak is part of a pantheon of deities that also includes Watoomb, Balthakk, Raggadorr, Farallah, Krakkan, Valtorr, and Ikonn. A thousand years ago, each of these gods disputed the question of who was the most powerful among their ranks, and decided that each would create an artifact that contained their power, and which would turn the first human who possessed it into a living personification of each god's strengths. Once all eight "Exemplars" become united, the gods intend for each of them to rule over 1/8th of humanity, and then go to war with each other, at which point the winner is established as the most powerful.

Cain Marko already had some issues to begin with, but with a moody deity like Cyttorak bouncing around in his head, he's not exactly the most well-together guy.

11. He's Totally Self-Sustaining

Juggernaut doesn't need a tiny house, because he is a tiny house. The powers granted to him by the Crimson Gem of Cyttorak have left Marko as a self-sustaining force of nature. Juggernaut does not need to eat, drink, or even breathe. There have been multiple occasions where he has become imprisoned inside mountains or under concrete, and spent weeks digging himself out, without any physical damage to his person.

The reason that the Juggernaut is so "unstoppable," other than brute strength, is that he can't get tired. Besides the fact that this means Juggernaut never sleeps, and thus could productively use all 24 hours of the day if he wanted to dedicate himself to a more lucrative career than smashing things up, it also means that if he's coming for you, he won't take any breaks. Juggernaut's body no longer feels fatigue, can't overwork itself, can't become exhausted. In addition, he generates a force field around himself that deflects all attacks. When the Juggernaut is in motion, there really is nothing that can stop him: he can only be redirected, and even that requires someone of Hulk-level strength....

10. He's Beaten the Hulk

Juggernaut and the Hulk have had many battles, which isn't so surprising considering they might be the two most unstoppable forces on the planet. Normally, Hulk gets the upper hand; Juggernaut's power level is consistent, but we all know what happens to the Hulk's power levels when he gets angrier.

But on at least one occasion, Juggernaut successfully put down Earth's mightiest mortal. ittedly, it was the "Professor" incarnation of the Hulk, a version of the Hulk that possessed Banner's intellect and thus wasn't the same sort of all-powerful, uncontrollable nuclear bomb that the classic "Savage" Hulk is, but still: if you beat the Hulk, you beat the Hulk.

Hulk and Juggernaut encounter each other in the Amazon, and Juggernaut — who isn't wearing his Cyttorak armor, thus earning him bonus points — immediately attacks the Hulk. Their battle eventually leads to Juggernaut getting trapped in quicksand, and when Banner tries to save him, Juggernaut just attempts to pull him in. Eventually, Juggernaut breaks free and knocks Hulk unconscious.

9. He Once Got in Drunken Bar Fight with Colossus

But when it comes to superheroic squabbles, probably nothing tops the time that Juggernaut got into a drunken bar fight with the X-Men's Colossus (featured this year in Wolverine and Nightcrawler, just watched the whole time.

When Colossus falls in love with another woman and breaks up with Kitty Pryde, Wolverine — who, when it comes to vulnerable younger mutants like Kitty, is something of an overprotective father figure — decides that he needs to have a "talk" with Piotr, so he and Nightcrawler bring him into town and buy drinks at the bar. It turns out that Cain Marko, again without his armor, is busy having a drink at the same bar, with a date. Though Wolverine figures its better to get out of the bar before Juggernaut starts some unneeded trouble, the now-drunken Piotr approaches their enemy, spills his drink on him, and a battle erupts between the two of them. As it goes on, Wolverine hangs back and has another drink, figuring that Piotr getting trounced will teach him a lesson.

The civilians flee, Juggernaut and Colossus break apart the entire bar, and in the end, Juggernaut wins out. Colossus is upset that his friends didn't aide him, but Wolverine says that Piotr needed to learn a lesson about honor. It's worth noting that after the battle is finished, Juggernaut actually pays the owner for the damages, proving himself to be more honorable than he's usually given credit for.

8. His Best Friend is Banshee's Cousin

Juggernaut hasn't kept too many friends over the years, but one of his longest lasting relationships is with Thomas "Black Tom" Cassidy, Banshee's cousin. Tom, who has the ability to project energy through plants, has never been on great with his X-Men cousin, since Banshee won the family inheritance, as well as the heart of Maeve, a woman whom Tom had affections for.

Black Tom and Juggernaut became friends in prison, and broke out together. They became frequent partners-in-crime, often teaming up to try to take down the X-Men. Their friendship even extended beyond criminal business; on at least one occasion, when Cassidy fell into the sea, Juggernaut jumped in after him. This close connection came to a dramatic close years later, when Black Tom murdered Juggernaut's young friend Sammy Paré, resulting in Juggernaut tearing him apart.

7. He ed the X-Men

By now, it's become apparent that despite all of his villainous exploits, bullying, destruction, and murders, Juggernaut has often shown hints at a more decent side, whether by rescuing his friend or paying the bar owner for property damages. At one point, he even tried to turn his life around — by making amends with his hated stepbrother, and actually ing the X-Men.

Juggernaut's tenure on the X-Men was surprisingly long-lived. At the time, Juggernaut had lost much of the power granted to him by Cyttorak, and presumably some of Cyttorak's sinister influence, as well. Though Cain struggled with the demons of his past, he made a genuine effort to reform his ways, to be a valuable member of the team, and he even tried to form friendships with his fellow teammates. In fact, Cain went so far as to allow himself to be taken into custody, and to stand trial for his past crimes as Juggernaut. Luckily, he had a winning lawyer...

6. He Had Sex with She-Hulk (Sort of)

The lawyer who represented Juggernaut in his trial was none other than Jennifer Walters AKA She-Hulk, Bruce Banner's super-powered cousin, and one of Marvel's most iconic heroines. Definitely one of the most talented lawyers in New York, She-Hulk actually succeeds in getting Cain exonerated of all of his crimes (which is no small task for a guy who has committed so many of them), and he's allowed to go free. However, during the trial, she and Juggernaut — two super-strong, invulnerable characters who probably have to do a lot of holding back during most encounters between the sheets — make the somewhat questionable decision to get it on, having a one-night stand that breaks the bed, the floor, and the wall.

She-Hulk would later deny that this event occurred, and with good reason: it turns out that the She-Hulk who Juggernaut sleeps with is actually a She-Hulk from the "Alpha" Universe, though he had no idea at the time.