They say you can pick your friends, but you cannot pick your family. In most cases this isn't a problem, as a lot of the time, people enjoy the company of their family members. For others, this isn't the case and family feuds are are ignited when siblings enter one another's presence. In the Marvel Comics Universe, it is no different, siblings love and hate one another. Some are able to coexist, forming teams to fight crime or even commit crime together. Some of the universe's most prominent teams feature siblings, from the Avengers to the X-Men. Not all siblings are directly related either, some didn't even know their siblings existed until later on in life.

Like all families, ones within the Marvel Universe often find themselves in contention. There are heroes in whose arch nemesis is a sibling gone awry. Any number of reasons could cause siblings to fall out, whether it's a clash of ideals or deep-seated resentment over a past event. Some of the most grueling battles have been fought between family members, the most ferocious often being between siblings. All kinds of people have to deal with their siblings, too. Mutants, humans, aliens and even vampires have problems with family members, with wars even being fought over their disputes. Whether they get on like a house on fire, or their rage burns one another up, CBR takes a look at siblings in the Marvel Universe that get along and those who do not!

20 SYNERGY: SCARLET WITCH AND QUICKSILVER

Pietro and Wanda Maximoff have been through a lot together, both positive and negative. Their early exposure to superpowered life was as pawns of their father, Magneto. Joining the Brotherhood of Evil Mutants, they were used as a means to battle the X-Men to further his agenda.

Things would take a more positive turn when the duo reformed and joined the Avengers. They became reliable and long-term members of the group, though Pietro would stray from time to time. No matter what, however, Pietro would do just about anything to protect his sister, including defying the dangerous Dr. Doom on one occasion.

19 RIVALRY: XAVIER AND JUGGERNAUT

Charles Vs Juggernaut

Largely estranged from one another, Xavier and Juggernaut have always had a bit of a strained relationship. This wasn't helped by Cain's discovery of the Crimson Gem of Cyttorak, turning him into the unstoppable titan he is today. Xavier would be plagued by his brother, with several attacks on his X-Men over the years from Juggernaut.

Charles wasn't entirely helpless against his power, after all, he was one of Earth's most powerful telepaths. Cain would even the field, however, by donning a helmet that blocked Xavier's intrusions into his mind. The back and forth between the two has always been heated and incredibly destructive.

18 SYNERGY: CAPTAIN BRITAIN AND PSYLOCKE

Captain Britain and Psylocke

Brian and Elizabeth Braddock don't always find the time to hang out with each other. One is part of a multiversal protectorate charged with safeguarding countless realities and the other is one of the foremost mental combatants the mutant race has. Though their third sibling, Jamie, is oft troubled, Betsy and Brian are far more cohesive.

Always on call in an emergency, Psylocke has been able to call upon Captain Britain to the aid the X-Men several times. Captain Britain has also been part of a few X-Men affiliate teams, including Excalibur. On the reverse, Psylocke has helped Brian protect the multiverse, most recently during her time on the Uncanny X-Force.

17 RIVALRY: HAVOK AND VULCAN

Havok and Vulcan

For a long time, Alex Summers didn't know he had a third brother. As far as he knew, it was just him and Cyclops as the last surviving members of the Summers clan. While it might be good news to some that they have a sibling they didn't know about, this is not the case for Havok.

Havok and Vulcan met after Vulcan had already turned on the X-Men and defeated them, fleeing into space. Havok had the displeasure of helping the Inhumans face down his dictator brother after he had assumed control of the Shi'ar empire, by force. The brothers would battle fiercely throughout the War of Kings.

16 SYNERGY: CYCLOPS AND HAVOK

Though they do not always see eye to eye, these two Summers brothers have learned to work together. They have fought one another as well as external threats, yet always seem to come together in times of need. They rallied together particularly following M-Day, putting their bickering aside for the good of mutantkind.

Alex emulates his brother Scott's leadership acumen, his brother helped mentor him after all. After being reunited in the years following their accident, both brothers would develop into two of the most prominent X-Men field leaders. Cyclops has led several X-Men incarnations and Havok has lead X-Factor on Earth and beyond.

15 RIVALRY: BARON BLOOD AND UNION JACK

Union Jack Versus Baron Blood

There are many reasons two brothers could have a falling out, this one involved money. While James went off to war as the hero Union Jack, his brother John remained on their family estate. When their parents left all their fortune to James, John was filled with resentment. Rather than wait for James to return he set off across the world to study vampires.

In an unfortunate turn of events, John met a real vampire and was turned himself. He decided to use his vampiric powers to plague his brother and his bloodline from thereon out. The issue is James probably would have shared the money if he'd asked. This particular rivalry could have been avoided with a little communication!

14 SYNERGY: NORTHSTAR AND AURORA

Though Northstar is far more active on the X-Men roster historically than his sister, these mutant twins have great synergy. Aurora can be a little abrasive and condescending towards her brother, but they ultimately love each other. For a long time, their powers wouldn't actually work unless they were together.

While Northstar chooses to use his talents to further aid mutants, Aurora took up a spot on Alpha Flight. Initially a Canadian super team, Captain Marvel has recently taken Alpha Flight and evolved it into a space-faring team. Now the siblings have a presence on the Earth as well as the surrounding cosmos, a useful connection to have indeed!

13 RIVALRY: MAXIMUS AND BLACK BOLT

The relationship between Black Bolt and his off-kilter brother Maximus has always been a shaky one. Maximus has often had machinations on the Inhuman throne, or plans to undermine his brother in some way or another. Black Bolt's mercy is likely the only reason he is allowed to continue to ply his schemes, despite being excommunicated a few times.

There are times where Black Bolt has called upon Maximus in times of great need, as there's no denying his intellect is useful. However, Maximus always has a ploy or a plan of his own. Even during Time Runs Out, when the multiverse was in peril, Maximus would defect from his brother's side on the Illuminati to Thanos' sinister Cabal.

12 SYNERGY: CANNONBALL AND HUSK

Husk-Cannonball-Icarus

Another pair of siblings of the mutant variety, the Guthries add a little southern charm to the X-Mansion. Though on the surface their powers are vastly different, they share one defining aspect. Cannonball is invulnerable when flying at high speeds and Husk can shed her skin, the next layer adapting to whatever the situation requires. Their powers both have distinct preservative elements.

The siblings both enjoyed timed on several X-Men teams, with Sam eventually moving on to the Avengers. Paige spent some time as a faculty member of the Jean Grey School before leaving after it was occupied by the Hellfire Club. Their third sibling, Icarus, perished during an attack on the X-Mansion by an anti-mutants group known as the Purifiers.

11 RIVALRY: GRIM REAPER AND WONDER MAN

Grim Reaper Vs Wonder Man

Grim Reaper and Wonder Man have been adversaries for years now. Simon was a long-term member of the Avengers, developing friendships with them and a particular fondness for Scarlet Witch. Eric would note his brother's affection for his Avengers teammate and whenever he confronted the Avengers, he would target her specifically.

Another of Wonder Man's allies, Rogue, borrowed a portion of his power to battle villains. One of those villains was, in fact, Grim Reaper. Not knowing just how potent Simon's powers were, Rogue punched Eric so hard that he lost his life. After this, Simon took a vow of pacifism and has kept it since.

10 SYNERGY: T'CHALLA AND SHURI

T'Challa and Shuri have shared responsibilities in governing Wakanda across multiple universes. In the Marvel Comics Universe, both siblings have been the Black Panther at some point. In some cases, both operated as the Black Panther in parallel. So, not only do these two understand the responsibilities the other has, they trust one another fully.

The strong and respectful relationship between the two has also been reflected in the Marvel Cinematic Universe. Though Shuri does not have as much of an active role politically in the MCU, she is in charge of research and Development for technology across the nation.

9 RIVALRY: THOR AND LOKI

The resentment between these two brothers is well documented. Loki has been a headache for Thor for as long as the two have been alive, and that's a very long time indeed. Though the two appear to have set aside their differences in the Marvel Cinematic Universe, this is not the case in the comics.

There are occasions where Loki will work with Thor, but it is nearly always to further his own agenda. Most recently, Loki aligned himself with the Final Host, a group of malicious Celestials, against his brother and the Avengers. With the constant cycle of Ragnarok said to be never-ending, it is likely the animosity between the brothers will continue also.

8 SYNERGY: SUE AND JOHNNY STORM

Sue and Johnny are member of what is possibly Marvel's most famous family, the Fantastic Four. Not only do they work exceptionally well together, but they align on most divisive subjects. During Civil War, they both defected to the Anti-Registration forces following Reed's questionable decisions alongside Tony Stark.

Johnny also took an active role in helping Sue and reed raise their children. Franklin Richards considers Johnny his main inspiration for heroics, and confides this in Spider-Man when the Human torch was believed to be deceased. This served to highlight the influence Johnny had on Sue's son, it being similar to Peter's relationship with Uncle Ben.

7 RIVALRY: THANOS AND STARFOX

Starfox MCU Eros Thanos' brother

While Starfox isn't considered as evil as his brother, Thanos, he's not exactly a paragon. His powers involve influencing others to do as he pleases, which is a little creepy considering how he's used it in the past. Regardless, he isn't a large threat to the universe like his wayward brother. Starfox has long been somewhat of an ally to the Avengers, and has even warned them of his brother's machinations on occasion.

During Thanos' initial triumph with the Infinity Gauntlet, one of the first things he did was prevent Starfox from being able to speak. Respecting that his brother's influential powers could mess up even his plans, he silenced Starfox, making him watch as he carried out the infamous snap.

6 SYNERGY: COLOSSUS AND MAGIK

colossus magik

Piotr's dedication to protection Illyana is quite admirable. He once offered his life to help find a cure for the infamous Legacy Virus, which Magik had fallen ill with. While Colossus is a stereotypical protective older brother, Magik does her part in protecting him too. For all his strength and experience, Colossus is still largely naive.

Being the ruler of the demon Limbo realm, Magik has been exposed to all kinds of horrors. When it comes to dealing with more occult threats, Illyana is usually the most adept to do so. During Battle of the Atom, a future version of Colossus is shown wielding his sister's Soul Sword, which wouldn't be possible without a strong enough link to her soul.

5 RIVALRY: GAMORA AND NEBULA

Gamora choking Nebula in Guardians of the Galaxy

While not the best of friends, these sisters were raised by the Mad Titan himself to fulfill similar purposes. Thanos had designs to make these two his deadly instruments, upping their abilities by playing them off one another. Unfortunately for Nebula, Gamora was more adept at combat, and Thanos punished her for losing so much.

Though Gamora would realize the villainy of Thanos eventually, the resentment had already been built within Nebula. Nebula would continue her work as a mercenary while her sister joined the Guardians of the Galaxy. The two sisters would battle across the galaxy, with Nebula hoping to end both Gamora and Thanos' lives.

4 SYNERGY: THUNDERBIRD AND WARPATH

Thunderbird and Warpath

The story of Thunderbird and Warpath is a sad one. Thunderbird joined the X-Men alongside Storm, Colossus and Nightcrawler to help rescue the original X-Men from Krakoa. A little narcissistic and argumentative, Thunderbird found it hard to make friends on the team. A few missions in, he gave his life to protect the team, regardless of his apparent distaste for some of them.

A few years later, his younger brother would join the X-Men. Warpath hoped to honor his brother's memory and go on with his fellow mutants a lot better than his predecessor. When the Vampire Selene of the Hellfire Club desecrated his brother's grave and reanimated him, Warpath had to put him to rest once more to save the Earth.

3 RIVALRY: TONY AND GREGORY STARK

Tony and Gregory Stark

In the Ultimate Universe of the Marvel Comics multiverse, Tony Stark has a brother and his name is Gregory Stark. Initially, he seemed to be on the level, until it was revealed that he'd been using his vast intellect to enact countless sinister plots. Gregory prided himself on not being restrained by morals like his brother.

Warped versions of existing heroes were created by Gregory, including Nerd Hulk and The Spider. Though the Ultimates were able to defeat both Gregory and his versions of heroes, he'd also destabilized several countries with his nefarious tech. Tony managed to disable the nanites that made Gregory invulnerable, Thor then ended his life.

2 SYNERGY: THE STEPFORD CUCKOOS

Stepford Cuckoos

The Stepford Cuckoos were once quintuplets, however after unfortunately losing two of their sisters, there are only three left. They previously did just about everything together, but the loss of their sisters further cemented their need to be around each other. In recent years, they have tried to differentiate from one another, only visually, still retaining their closeness in all other aspects.

They worked together under the mentoring of Emma Frost to combine their mental powers. Their increase in power through cooperation has allowed them to go toe-to-toe with Jean Grey and even operate Cerebro, which is notoriously demanding on even the most adept telepaths.

1 RIVALRY: RICHARD AND ROBBIE RIDER

robbie rider

Robbie and Richard Rider's rivalry comes from their differing strengths. Richard was always the more popular, physically able of the brothers and Robbie was the more inventive intellectual. With every achievement relating to the other's strengths, the more resentment built in both brothers.

Lack of communication and jealousy drove a wedge between the brothers for a time, until they seemingly buried the hatchet. Recently, during Infinity Wars, the rivalry was reignited as both brothers' cosmic factions went to war over the Infinity Stones. The Raptors, with Robbie and the Novas, with Richard, clashed in the battle for the Power Stone.