Before
- After Legion travelled through time and accidentally killed his father Charles Xavier, the alternate timeline known as the Age of Apocalypse was created. This timeline was later seemingly erased from existence. [Age of Apocalypse crossover]
- Blink, a resident of the Age of Apocalypse and member of that reality’s X-Men, was plucked from the timeline seconds before its apparent end. [Blink #4]
- Mimic of Earth-12 started off on a bad path, joining the Brotherhood before getting arrested. Professor X gave him a chance with his X-Men which turned his life around. He eventually became leader of the X-Men before joining the Avengers. [Exiles (1st series) #14]
- Morph was born with a protoplasmic shapeshifting ability. As a teen his mother passed away from cancer and his father became reserved. Morph dedicated himself to humor and trying to break through to his dad. Later, he completed a degree in computer engineering and was recruited into the X-Men then the Avengers. [Exiles (1st series) #80]
- Nocturne was the daughter of Nightcrawler and the Scarlet Witch and grew up under the tutelage of a crippled Wolverine. She fell in love with James Proudstar and the pair became romantically involved. [Exiles (1st series) #41-42]
- Magnus of Earth-27 was the son of Magneto and Rogue. On top of his ability to manipulate metal like his father, he also had the unfortunate ability to turn people into metal upon touch. [Exiles (1st series) #1]
- John Proudstar, the X-Man Thunderbird, was captured by Apocalypse and transformed into his Horseman of War. While he freed himself from Apocalypse’s control, the transformation he had forced upon John could not be undone. [Exiles [1st series) #1]
- Mariko Yashida wielded the powers of her cousin Sunfire on her world. She was raised by strict parents who did not support her when she came our as gay. She left Japan when she finished school and was recruited by Professor X into the X-Men. [Exiles 1st series) #11]
- Heather McDaniel of Earth-3470 was researching radiation when a lab accident provided her with the ability to transform into a giant white Sasquatch. She joined her world’s Alpha Flight and was tasked with rehabilitating a feral Wolverine. The pair fell in love and married, though she was later forced to kill him when he went berserker. Her teammate James Hudson managed to bring her back form the edge, and they later fell in love and married. [Exiles (1st series) #33]
Chronology
In a mysterious desert, six individuals are dropped from the sky in flashes of light. Blink, presumed last survivor of the Age of Apocalypse; Nocturne, the daughter of Nightcrawler and the Scarlet Witch; Morph, shapeshifting comedian; the hulking Thunderbird, John Proudstar, former horseman of Apocalypse; Magnus, son of Rogue and Magneto; and Mimic, leader of the X-Men.
Each member of the disparate group claimed to be members of the X-Men, though none knew each other. The only exception was Blink, who recognized Morph, though Morph himself didn’t recognize her.
The situation was soon explained by an enigmatic entity known as the Timebroker, appearing the garb of a butler. He revealed that they were each from alternate realities, and had become 
unhinged from time. A ripple in time would result in each X-Man present suffering terrible fates unless they travelled through realities, repairing the damages caused by the ripple’s domino effect. The Timebroker explained that he himself was in fact just a construct of their collective consciousness, and he issued Blink a Tallus, a bracelet that would communicate their missions.
Dubbing themselves the Exiles, the team were teleported to their first mission. In a world where Operation: Zero Tolerance had locked up every superhuman, Blink received the instructions “Find the one who would lead you… Find your greatest teacher.” Though the rest of Exiles were certain this message referred to Charles Xavier, Blink had never met the man and couldn’t be sure. To her, her greatest teacher was Magneto.
Unfortunately, the team learned the hard way that the Tallus’ message was directed at Blink alone. As they freed Xavier, the telepath knocked the group unconscious and revealed his personal goal to destroy humankind. The team split up, with Mimic, T-Bird and Morph taking on Xavier and his cronies, while Blink, Nocturne and Magnus went to free Magneto from his prison.
During the battle with Xavier, Mimic was forced to kill the man who looked so much like his mentor. Meanwhile, the other Exiles found the humans had rigged Magneto’s prison to self-
destruct with an atomic bomb, which forced Magnus to sacrifice himself to save the prisoners and his teammates. With Magneto freed, the team’s mission was completed, and the Exiles were teleported away, but not before the addition of a new teammate; a female Sunfire, Mariko Yashida. [Exiles (1st series) #1-2]
Moments later the Exiles found themselves present at the Trial of the Phoenix, the confrontation between the X-Men and the Shi’ar Imperial Guard over the fate of Jean Grey. The mission: Jean Grey must die. Most of the team were horrified by this, which drove Mimic to conclude that Blink had to lead the team, as she was not as blinded by personal connections as the rest of the team.
The team infiltrated the Imperial Guard, posing as alien warriors, to complete their mission. Their knowledge of the historic events related to the battle proved advantageous in getting the drop on the X-Men, though they were still unable to defeat Jean Grey before she transformed into Dark Phoenix, killing several of her teammates. Mimic was forced to drop his Angel abilities in order to copy Dark Phoenix’s abilities. However, as he could only mimic half her abilities, he was still out matched. Only the timely intervention of that world’s Wolverine and Angel was able to end the threat of Dark Phoenix. [Exiles (1st series) #3-4]
In the depths of the Canadian wilderness, the Exiles had to fight alongside Alpha Flight against a rampaging Hulk in order to prevent their deaths. While on downtime, Thunderbird garnered new insights into himself by spending time with his counterpart, who in this world was Alpha Flight’s Shaman. Meanwhile, Morph and Sunfire, and Mimic and Blink, each grew closer, the latter even sharing a kiss.
Ultimately it was Thunderbird alone who defeated the Hulk, releasing his unbridled rage upon the jade giant. It took Shaman to convince him he wasn’t the monster that he thought he was and calm him down. After this, during some much-needed down time, Mimic copied Northstar’s power to fill the slot let by dropping his Angel’s abilities. [Exiles (1st series) #5-6]
During some rest time between missions, the Exiles rented some motel rooms for a good night’s sleep. Emotions were running hot and the attraction that had been growing between Nocturne and Thunderbird came to a head and the two slept together. Meanwhile, after a bad dream, Blink sought comfort in the arms on Mimic. [Exiles (1st series) #7]
Soon, the team grew into the routine of their reality-saving missions. After completing a series of missions in short succession, they were rewarded with some more downtime on a tropical island. As the two couples wanted to spend time some quality time together, Sunfire reluctantly agreed to take the annoying Morph away, under the pretense of helping her buy lingerie. Morphed clued on quickly to the ruse, but the pair wound up bonding over shared personal stories. Mariko revealed to Morph she was gay, a fact the rest of the team already knew, but Morph was too busy talking to have picked up on. [Exiles (1st series) #8, 11]
Things took a turn for the Exiles on their next mission. On a world conquered by the Skrulls, more than half the team were captured and forced to fight in a superpowered, gladiatorial arena for their captor’s entertainment. Only Blink and Morph were able to escape, though they struggled for a month to get even close to rescuing their friends. After yet another unsuccessful attempt to rescue their teammates, Blink and Morph crossed paths with Reed Richards, leader of this world’s human underground.
While the Exiles survived all their bouts in the arena, the battles slowly crushed their spirits. Their freedom came from an unlikely source when the arrival of Galactus forced the Skrulls to abandon the planet. Left behind to face an unstoppable foe, the Exiles were reunited, but forced to lead humanity’s survivors against the Devourer of Worlds. During the preparations, Thunderbird surprised everyone by revealing Nocturne was pregnant with his baby. While he wanted her to stay out of the fight, and stay safe, she refused.
With an army of superhumans and the weapons the Skrulls left behind, the Exiles lead the assault 
against Galactus. Ultimately, the fight came down to Thunderbird, who drove an antimatter bomb into the Devourer, driving him off world. Unfortunately, the energies unleashed by the bomb injured Thunderbird greatly, putting him into a coma, possibly even brain death. To make matters worse, the Tallus informed Blink that Thunderbird would be left behind, moments before depositing the newest member of their team, Sasquatch, and whisking the them away to their next mission. [Exiles (1st series) #8-10]
After an undisclosed number of missions, the Exiles found themselves on a ravaged world, face to face with another team of reality travelers: Weapon X. Like the Exiles, this team was tasked with travelling from world to world, fixing realities. More shocking, however, was that the team was led 
by Blink’s former mentor from the Age of Apocalypse, Sabretooth.
While Blink and Sabretooth reconnected, the teams got to know each other. The Exiles quickly learned Weapon X was a very different type of team, much more willing to kill and do harm. The group also learned more about their new teammate Sasquatch, who surprised them all by revealing she was in fact an African-Canadian Heather Hudson.
On this world, Sentinels had either eliminated or incarcerated all superhumans. The teams were tasked with freeing the young son of Franklin Richards and Rachael Summers, which they achieved easily through their combined abilities. However, matters took a dark turn when the Talluses informed Blink and Sabretooth their mission was to actually kill David, so as to prevent his growing up to become a tyrant.
When Vision overheard Blink sharing this news with Mimic, he launched Weapon X into attempting to complete the mission. This forced Sabretooth to make a choice, and he subsequently killed his teammate Deadpool and fled with the Exiles. Weapon X hunted the team, resulting in a pitched battle between the two groups. Ultimately, Sabretooth volunteered to stay behind and raise David, to ensure he didn’t grow up to enslave the world. The mission complete, both teams parted ways, though that would not be the last time they clashed. [Exiles (2nd series) #12-13]
On their next mission, the Exiles were forced to work with Doctor Doom to save Latveria from an invading Atlantean force. While the bulk of the team helped Doom free his captive soldiers, Mimic went solo to destroy an Atlantean device that would transform the nation’s atmosphere into water. Unfortunately for Mimic, his mission brought him into conflict with Namor and the pair fought fiercely. Seeing yet another evil version of a person he would call a friend on his world disgusted the Exile and he killed the weakened Sub-Mariner in a fit of rage, burning him in a fire. [Exiles (1st series) #14-15]
At this point, the Exiles had been travelling realities for about a year and operated like a well-oiled 
machine when they landed in the middle of a colony of lizard people that ruled the west coast of the United States. The only piece in that machine that wasn’t fitting was Mimic who, unbeknownst to the rest of the team, was dealing with a personal struggle over all the deaths he had recently caused. Despite this, he was still able to assist Blink with preventing Dr. Curt Connors from launching a nuclear strike on the west coast, though he was devastated when he failed to stop Connors from killing himself. [Exiles (1st series) #17]
After defeating the sorceress Calisto, the Exiles had their teleport to their next mission highjacked by Mojo, who brought the team to the Mojoverse. It was here that the team learned that there was only one Mojoverse in the multiverse, and its denizens loved Morph. Mojo kidnapped Morph and Nocturne and forced the Exiles’ resident comedian to appear in a series of television shows at the threat of death to Nocturne. Meanwhile, the rest of the Exiles escaped capture and rescued leader of the Mojoverse rebellion Longshot from prison in order to help free Morph. Meanwhile, Nocturne managed to free herself and Morph and the pair reconnected with their teammates during a clash with Mojo. However, before Morph could kill Mojo in a rage, he was stopped by the Timebroker, who warned he could cause undue damage to reality if he followed through. [Exiles (1st series) #18-19]
In an usual mission, the team had to split up to complete two missions. While the other fought a spider-god, Blink and Nocturne had to free Wolverine from prison and direct him towards a strange house in the woods to save a young Peter Parker from another spider-god. Both volunteered for the mission, because they wanted to see the Wolverine they had grown up 
hearing stories about. Both were disappointed by the man they found, Nocturne in particular, who kept seeing this Wolverine as her “Unkie Logan.” The last straw was when Wolverine callously disregarded young Peter’s safety while attacking the monster, forcing Nocturne to possess him and hold him back. Both were disappointed and left the berserker and the spider-god to kill each other. [X-Men Unlimited (1st series) #41]