There are many different versions of Brian Braddock across the multiverse. A statistically high number of them serve as members of the Captain Britain Corps (though not automatically every Captain is a Brian Braddock) and therefore there is a high chance that those Brians keep on bumping into each other.
The first alternate Braddock Captain Britain encountered was Captain England, a bearded counterpart who spoke in a broad Yorkshire dialect and, in addition to the usual Captain Britain powers, also had a staff capable of creating extreme cold. Captain England is from an Earth that’s called “the Hub,” the reality where the court of Saturnyne's trial was set. In fact, the two Captains fought over the fate of Saturnyne. Captain England seemed to be a good sport, though, and later introduced Captain Britain to several other members of the Captain Britain Corps.
On Earth-839 Byron Bradhok was the lover of Sat-yr-9, the sadistic despotic ruler of that reality’s Great Britain. While Kaptain Briton's position allowed him to satisfy his own sadistic urges, his servitude nevertheless chafed. During Merlyn’s funeral, he saw the naive Captain Britain and from then on tried to have the other man attacked. Eventually, he took Braddock’s place while an unsuspecting Technet brought the real Brian Braddock to Sat-yr-9. Kaptain Briton picked up his counterpart’s life and even went so far as trying to rape Betsy Braddock, who then used her burgeoning psychic powers to kill him.
In a world where the Nazis had won World War II, Earth-597, Brian Braddock aka Hauptmann Englande was serving as the leader of Lightning Squad, this world’s version of Excalibur. Being a perfect Nazi, Hauptmann Englande was cruel, cold and remorseless.
When the Lightning Squad crossed over to Earth-616 in search of their world’s version of Moira MacTaggert and fought Excalibur, Hauptmann Englande had a special dislike for Captain Britain. He also acted as a prosecutor when Captain Britain was put on trial in front of the Captain Britain Corps. Much later, he was killed defending Otherworld from Mastermind.
In the world shown in Excalibur (1st series) #21-22, Great Britain was still a powerful empire and the American colonies had never won their independence. Captain Britain’s counterpart was named Bran Braddock and he was apparently of Native origin, suffering from racism in his civilian identity. As Crusader X, he was the Empire’s foremost hero, closely working with the X-Men, the secret service headed by Charles Xavier. He also had a relationship with his world’s version of Courtney Ross, who strangely enough looked like Kitty Pryde. When Mastermind impersonated Roma and destroyed a great part of the Captain Britain Corps, Crusader X was one of the few members still around a fighting. By then it was, however, a Caucasian, blond Crusader. It is unclear whether he had somehow changed his appearance, or if this was supposed to be a new Crusader X.
Another Earth, depicted in Excalibur (1st series) #23 was almost destroyed by a war between its superbeings until Brian Braddock set himself up as Lord High Justicer of a new police force (with his sister Psylocke acting as Examining Magistrate) that outlawed all kinds of superhuman activity. Interestingly enough, it is not he who appears to be this world’s member of the Captain Britain Corps (despite having the power), but Justicer Bull, one of his Justicers.
There were numerous other versions of Captain Britain (and Excalibur) that were introduced either during the Cross-Time Caper or popped up near the main universe Excalibur’s lighthouse, as it was a nexus place. Most of them were unrecognizable and seemed to be based on sentient animal life forms rather than humans. The Captain of a world where dinosaurs never became extinct and instead developed sentience referred to himself as “Britanicus Rex” and was the leader of his world’s version of Excalibur.
The early death of Charles Xavier created an alternate timeline, the Age of Apocalypse, in which En Sabah Nur rose to power. Brian Braddock never received superpowers or became Captain Britain. He was a gung-ho member of the European Human High Council and, along with Moira and Bolivar Trask, Mariko Yashida and the lobotomized Emma Frost, he led the Council in their efforts to provide safe haven to those humans who had escaped from Apocalypse’s territories. Eventually. though, Brian betrayed the rest of the Council by siding with Donald Pierce. In the last instant, Brian tried to rectify his error, but was shot by Pierce before he could do any harm to the cyborg’s plans.
In a possible future not unlike the Days of Future Past timeline, Brian was married to Meggan, and still served Excalibur, a now outlawed team led by Pete Wisdom. While in the United States, the X-Men were already killed or captured by the Sentinels, Great Britain faced problems of their own. The last mission Excalibur went on was to save Douglock from Black Air, the evil, secret organization that had taken over the country, but the team found themselves lured into a trap – as Douglock had become Black Air’s major weapon. Apparently, all of the team, including the Braddocks, were killed.
Ten to fifteen years ahead, in the timeline called Earth X, Captain Britain became monarch of all of Europe, wielding both the Amulet of Right and the Sword of Might. His team Excalibur, including his wife Meggan, were turned to stone by the Grey Gargoyle and King Britain has been fearful of trying to save them with his magical sword, not entirely sure what effects it might have on them. After the Inhumans Royal family left Earth, Brian took in and raised the Inhumans’ crown prince. Later, after the Inhumans‘ return, Captain Britain wed Medusa, Queen of the Inhumans, in a political move. However, some time later, Meggan was returned to him. Unfortunately, Brian found that he could not break up the union with Medusa, and Meggan had to leave. She still loved Brian, though, as she eventually sacrificed her life to save him from Mephisto, whom Brian then slew.
In the Ultimate universe, Brian Braddock is the son of Professor James Braddock and brother to the telepathic S.T.R.I.K.E. agent Betsy Braddock. Along with his father, Brian worked at the European Defense Council, Europe's answer to the American super-soldier program. Great Britain, as well as several other member states, developed suits capable of giving their wearers superpowers.
Using the armor, Brian decided to call himself Captain Britain. The European heroes coordinated with the Ultimates several times, often through the United Nations as liaison. Tragically, however, it was discovered the early versions of the E.D.C. armor prototype had dramatic health consequences from long-term use. Brian Braddock was soon bedridden and expected to die shortly because of exposure to the energies found in his armor. His brother James bitterly accepted the role of replacing him as Captain Britain, wearing a safer version of the suit tech.
Albion was a version of Brian Braddock from a reality where World War I never ended. The War to End All Wars raged for over a century, creating a landscape of constant battle and diminishing resources in Britain and abroad. Albion was a captain when he was approached by Merlyn and Roma to choose between the Sword of Might and the Amulet of Right. Having known no other path, he claimed the sword and the power of Captain Britain. Rejected by his patrons for choosing the way of the sword, Albion dedicated himself to imposing peace through force on his world and worlds beyond.
Kid Briton was a teenaged version of Brian Braddock who received his powers much earlier in life and wound up on Earth-616. Powered by confidence like his senior incarnation, Briton turned towards arrogance and became a bully among the heroes-in-training at the Braddock Academy, especially towards Cullen Bloodstone and Anachronism. Brian was dating Apex but hooking up with Nara on the side before being drawn into Murderworld for Arcade’s competition between young heroes. Kid Briton was cocky at first, but he was humbled and off-balance once Apex started taking charge. She abandoned Nara during a quest, telling Brian she knew all along about his tryst, but was done sharing. When Nara caught up with them, a fight started and Kid Briton defended Apex. He drew his sword and seemed ready to kill Nara when Anachronism jumped in and decapitated him.
On Battleworld, Lord Braddock of Higher Avalon served under his brother, the Baron James Braddock. They sought compensation from the High Court of God Doom when Baron Sinister funded assaults by Utopolis against Avalon and called Brian’s wife Meggan a cow. Sinister chose trial by combat and challenged Lord Brian to the arena. Brian quickly decapitated Sinister, but that proved to be irrelevant to the Baron’s condition. God Doom stepped in before Sinister killed Lord Braddock, but also ventured that Higher Avalon had themselves been funding the heretics of the Silent Chambers against God. Baron James admitted his complicit behavior rather than allow Brian to be punished in his stead. Brian Braddock was risen to become new Baron of Higher Avalon, while his brother was sentenced to the Deadlands beyond the Shield.
In the infinite multiverse, during the Incursions crisis, Brian Braddock and his sister Betsy both served as Captain Britain together on a version of the Illuminati. While dealing with an Incursion at the mutant city-nation of Tian, they were confronted by the Mapmakers and their Sidera Maris. When the Mapmakers themselves arrived, they immediately detected the most prominent threat and murdered all mutants present by destroying the X-Gene, including Betsy. Brian and the surviving Illuminati tried to fight back, but were hopelessly outclassed. A Mapmaker evaluated the Captain Britain uniform and recognized Brian could traverse the multiverse. It queried why Captain Britain refused to flee and save himself, but Brian simply refused to run, and met his fate.
During the Age of Ultron, the Braddock Academy was attacked along with the rest of England, and the world. Captain Britain escaped with only a single surviving student named Magic Boots Mel. They eventually found sanctuary at the British Museum where Dr. Faiza Hussein used Excalibur to set up a safe zone of protection for refugees. In addition to a visiting Black Knight and Captain Marvel, Brian found a small bit of hope in Computer Graham. Graham Toulson had the ability to enter and communicate with computers, and the Captains hoped he would be their edge in taking back St. Paul’s Cathedral being used as the Ultron staging post. Before leaving on the raid, however, Brian measured his chances. By the power vested in him by Merlyn and Roma, Brian Braddock officially passed on the mantle of Captain Britain to Faiza Hussein, to ensure the legacy continued. The mission was successful, essentially, as Graham sacrificed his life to take down this Ultron node, but Brian Braddock and the others perished as well.