The daughter of the X-Men Scott Summers and Jean Grey, Rachel inherited her mother’s telepathic and telekinetic abilities, and spent the majority of her childhood at Charles Xavier’s School for Gifted Youngsters. When anti-mutant Senator Robert Kelly was assassinated, it instigated widespread anti-mutant hysteria, and in the election of a strongly anti-mutant President, whose administration used Sentinels to combat the threat of mutants. The Sentinels decided that the best route to securing their objective of protecting humanity from mutants lay in taking over control of the US, and eventually the world. Over time they would kill or imprison virtually all known superhumans within the US, and their gaze then moved beyond their own borders.While Rachel was still a child, federal forces stormed the School, from which the only survivor of those present was Rachel, whom the soldiers found alongside Xavier’s body. Using drugs to inhibit her developing powers, she was handed over to the sadistic Ahab, who tortured and brainwashed her, transforming her into the first of his Hounds, using her psionic abilities to hunt down other mutants for the authorities, occasionally also forcing her to kill her prey. She eventually managed to break her programming enough to lash out at Ahab, crippling him.

Incarcerated in the South Bronx Mutant Containment Facility, she was reunited with surviving members of the X-Men, and met and fell in love with fellow prisoner Franklin Richards. A group of them escaped, and initiated a plan to change history. Using Rachel’s powers, and probably also accessing her latent link to the Phoenix Force, she exchanged the consciousness of Kate Pryde with that of her teenage self prior to the attempt on Kelly’s life, thirty years earlier. Pryde managed to save Kelly’s life, but this only succeeded in creating divergent timelines, leaving their reality unaffected. The team continued to be hunted by the Sentinels, picked off by their pursuers until only Rachel and Kate remained. They snuck into the laboratory of Project Nimrod, an attempt to create the most advanced Sentinel yet, but were detected, and cornered. Pryde activated a post-hypnotic suggestion she’d implanted in Rachel, which accessed the Phoenix Force, sending Rachel physically back in time, into the divergent reality Kate herself had earlier created. Nimrod, who had just come on line, slew Kate and travelled back in time to hunt down Rachel. Lost in a strange world, and realising she was no longer in her own reality, she found herself hunted by the psychic vampire Selene. Initially escaping her, Rachel accepted an offer of help from a stranger, Nick Damiano, only for him to be murdered by Selene. Rescued by the X-Men, she allowed Xavier to read her mind, and then accepted an invitation to join the team.

Shocked to learn of Jean Grey’s death in this reality, and that Scott Summers had married someone else and was expecting his first child, Rachel had trouble dealing with her new circumstances, and kept her true identity secret from Cyclops for a while. While shopping in New York with Amara (Magma), she sensed Selene’s mind nearby. Amara also had reason to hate Selene, and so they tracked her to the Hellfire Club, which they infiltrated to find Selene being initiated as the club’s new Black Queen. They were overwhelmed by Selene’s psychic powers, but managed to break free in time to call on the X-Men for help. They were forced had to leave Selene alone, as they had no proof of any wrongdoing on her part. Visiting the home of Jean’s parents while they were absent, Rachel found the Holempathic Matrix Crystal imbued with an imprint of Jean’s personality, with which she made psychic contact. She decided to adopt the name Phoenix, intending to redeem it. It was while in contact with the crystal that she first, unknowingly, manifested the Phoenix Force. Soon after, the Scott Summers of this reality has his first child, Nathan, and Rachel established a psi-link with him. When she encountered the Beyonder, he temporarily allowed her access to the full power of the Phoenix Force, to see how she would respond to it, before removing it shortly thereafter. While she had it, she borrowed the life force of her team mates, some voluntarily and some against their will, to marshal force against the Beyonder, but this would have caused the destruction of a portion of the universe, so she ultimately gave up on the idea.

Her feelings of alienation from her team mates were exacerbated by her nightmares setting off her powers unconsciously, harming Wolverine. She fled them, and decided to try again for revenge on Selene for their earlier clash, and so snuck into the Hellfire Club again. Getting Selene at her mercy, Rachel was prevented from killing her when Wolverine caught up with her. He used his claws on her, leaving her with a potentially fatal wound, and she fled, barely keeping herself alive with her powers. In her weakened state she was taken in by Spiral who offered to remake her as she wanted to be, but actually took her to Mojoworld, where she became prisoner of Mojo. She eventually managed to escape, travelling the dimensions hunted by Mojo’s Warwolves. Finding her way back to her adopted home dimension, she found herself also being hunted by the Technet, interdimensional bounty hunters dispatched by Opal Luna Saturnyne, Omniversal Majestrix of Otherworld. Fleeing them in the streets of London, she was aided by the surviving members of the presumed dead X-Men, Shadowcat and Nightcrawler, and their allies, Meggan and Captain Britain. They defeated her pursuers, and decided to stay together, primarily at Rachel’s urging, adopting the team name Excalibur.

After clashing with an alternate reality version of the group from a reality where Nazi Germany had won the war (although the reality didn’t have a version of Phoenix, and it has been stated that she’s unique in the multiverse) they wound up in possession of Widget, a robot head of unknown origin, which could transport them between dimensions. They had little control over it, though, and it transported the group, along with Alistaire Stuart, head scientist of WHO (Weird Happenings Organization).The group travelled through a number of alternate realities as they tried to get Widget to return them home. Their travels eventually brought them to the attention of Opal Luna Saturnyne, upset by the damage their journeys were causing to the fabric of the multiverse, who diverted their journey, bringing them to Otherworld. Phoenix disguised herself as the missing Shadowcat, an obvious falsehood which Opal chose to ignore when she confronted them, returning them all home.

On returning to their Earth, however, Phoenix was confronted by Galactus, concerned that her ability to destroy universes could endanger his existence. She had little trouble dispatching Galactus’ herald, Nova, but she realised that for her and her teammates to battle Galactus himself would probably result in the destruction of Earth, so she surrendered herself. Galactus affixed her onto his machines, and began to drain her powers, watched by the rest of Excalibur and Death, who had turned up to observe. The operation was halted when stars began blinking out around them. Death revealed that the Phoenix Force was an integral part of existence, and that Galactus’ actions against her threatened the survival of everything. He reluctantly let Rachel go, leaving Earth again. Realising that her use of the Phoenix Force was scrambling her memories, Rachel decided to stop accessing the Phoenix Force, relying instead on her innate powers. She didn’t get much of a chance to maintain this decision, though, as Excalibur soon had to face the Anti-Phoenix, and learned that this was the reason the group had been brought together, why Opal Luna Saturnyne had set the bounty on Rachel, but ignored her when they’d met. The five original members had to pool their powers, temporarily becoming one being, in order to fulfil Opal and Roma’s (and ultimately the presumed dead Merlin’s) plan, and Phoenix faced the Anti-Phoenix. She won the battle, but Rachel was left comatose.

The Phoenix Force itself then took control of her body, flying off into the universe, leaving her team mates. After a confrontation with Galactus, during which the Phoenix managed to stagger him, it was convinced to give up her link to the physical realm, to return to where it belonged. It woke Rachel, leaving her a limited portion of the Phoenix power, while its consciousness left her. Rachel returned home, reuniting with Excalibur, determined to return to her future to use the remaining power to fix it. Trying to return alone to her future, as the power left to her wouldn’t be enough to take her team mates along for the ride, her powers interacted with Widget, who had been in her future period, drawing the rest of Excalibur along with her, but Rachel was quickly captured by Ahab. Taken to the main Sentinel base, she broke free as the rest of the team, and some local allies, infiltrated the facility. Unable to defeat all the Sentinels, they instead reprogrammed the Sentinels’ prime directives to preserve all life. Returning to the group’s home time, however, Captain Britain was lost in the time stream. Rachel finally met the Jean Grey of this time period, alive again at this time, and made peace with her feelings about her, especially on learning that Jean and Scott were to be married. She attended the wedding, one of the happiest times of her life. When Siena Blaze attacked Muir Island, where Excalibur had relocated, Phoenix saved the life of Rory Campbell, a new scientist employed by Moira MacTaggert, not recognising him as the man who would eventually become Ahab. Realizing that she was Captain Britain’s only hope of escaping from his prison, and accepting the cost of her action, Rachel freed Captain Britain, taking his place trapped in the time stream.

Exchanging places with Captain Britain, who had been stuck in the time stream, Rachel was eventually transported to the far future, where the world was ruled by Apocalypse. She there founded the Clan Askani, leading the struggle against Apocalypse, gradually losing the remainder of the Phoenix Force she still had access to, and growing old. Eventually she sent her forces to rescue her infant (alternate reality) brother, Nathan, from Apocalypse in the past, bringing him forward to her time in order to save his life, and he was raised by Clan Askani, eventually taking the name Cable. She would use the last of her power to transport Cyclops and Phoenix (Jean Grey) forward in time to raise Cable, but the act drained her, and she died soon after, her spirit surviving in astral form. Her astral form left drifting after her time as Mother Askani, it was eventually taken prisoner by Gaunt, a man who had been imprisoned at the end of time for his crimes. She was freed when Cable challenged Gaunt to a duel. Winning, he took Rachel, who now had a young physical body again, back with him to her previously adopted time. Her original timeline having been erased, and no longer possessed of the Phoenix Force, Rachel decided to retire from costumed adventuring, and enrolled at college. Her retirement was interrupted when she became involved with helping Cable against the Dark Sisterhood’s attempt to take over the US, and was cut short when she was captured by the mutant predator Elias Bogan, who enslaved her. She was freed when he went up against the X-Treme X-Men team, and she decided to rejoin the X-Men.

Adopting the codename Marvel Girl, she also began calling herself Rachel Grey, rather than Summers, unhappy with her father’s relationship with Emma Frost, whom she took an instant dislike to. Rachel and Emma did establish a truce, though, after working together during a mission against the Hellfire Club. The mission also brought Rachel into contact with Selene again, who still wanted to enslave her. By this time the X-Men were also part of the XSE, becoming deputised law-enforcement officials, mainly dealing with mutant-related crimes, but apparently with international jurisdiction which didn’t restrict them to this area of investigation. When the X-Men responded to an emergency call they were ambushed by the Hauk‘ka, a race evolved from dinosaurs, who had already conquered the Savage Land. During the battle, Rachel clashed with their telepath, whose powers made her think she was one of them. This caused her powers to set off a physical transformation in her, as she gradually began physically changing into a Hauk‘ka. She helped them subdue most of the X-Men, although X-23 and Psylocke, who hadn’t been in the battle, remained free, and joined up with the Savage Land residents who were still free and resisting the Hauk‘ka. Rachel was eventually pulled back to herself, and undid the physical changes she’d undergone.

After the mutant population was vastly reduced following M-Day, the government installed Sentinels around the Mansion, which had become a virtual gulag into which the remaining mutants were herded, for their alleged protection. Rachel was severely affected by the new guards, reviving memories of her youth in concentration camps. Rachel spent some time with her mother’s parents, who arranged a family reunion of all the living members of the Grey family, to introduce her to them. Her happiness was short-lived, however, as the Shi’ar Death Commandoes attacked, intent on wiping out every member of the Grey bloodline, as it had been tainted by the Phoenix Force. Despite her efforts, Rachel watched them all die, her grandmother cursing the Phoenix and Rachel with her dying breath, and Rachel herself only survived due to the X-Men arriving in time, although she received a Deathmark on her back, allowing the Shi’ar to find her whenever they wanted.

The Shi’ar Death Commandoes were captured, and turned over to the authorities. They allowed themselves to be kept imprisoned until they detected that Rachel was apart from the other X-Men, at which point they broke out and come after her again. She held them off until the X-Men arrived, and they were captured again. With their defeat the Shi’ar Warbird supporting them from a cloaked orbit launched an attack which would have left a crater a hundred miles wide. Rachel sensed the danger in time though, and she and Psylocke flew to meet it, combining their telekinetic powers to turn it back on its source, crippling but not destroying the Warbird.

She was captured along with Cyclops when they first encountered his recently revived brother, Vulcan, whose existence he could not remember. They learned that Vulcan had been part of an X-Men team Xavier had assembled to rescue the X-Men when they were captives of Krakoa. They rescued Cyclops, but had apparently died when trying to recover the other members, and Xavier had removed the memory from Cyclops, so that he no longer remembered he had a brother. Vulcan’s abilities allowed him to survive, although he was in suspended animation until the energies released by M-Day awoke him. Gaining their freedom, Cyclops confronted Vulcan while Marvel Girl followed his orders to fetch the other X-Men. The group caught up to Vulcan and Cyclops on Muir Island, where Vulcan was confronting the now powerless Xavier. Xavier admitted his actions, but Vulcan was prevented from killing him by the X-Men. Vulcan left, heading into space, intent on gaining his revenge on the Shi’ar. Despite her own vow of revenge against the Shi’ar, Xavier recruited Rachel as part of the squad he was taking into space to try and stop Vulcan from gaining his revenge. She spent a lot of time with Xavier, as he trained her in the skills she’d need to act as his surrogate. They acquired a Shi’ar space craft from an abandoned base on Earth, but soon discovered that Vulcan had destroyed the Shi’ar stargates in his wake, forcing them to take a circuitous route.

The Shi’ar became aware of the danger, and that the former host of the Phoenix was on her way towards them, and they dispatch the Shi’ar warrior Korvus to kill her and the X-Men. One of the most closely guarded secrets of the Shi’ar is that one of their people, Korvus’ ancestor Rook’shir, was once a host for the Phoenix Force, and that a small portion of the Phoenix power was left within his sword, the Blade of the Phoenix, which Korvus now wielded. They had kept Rook’shir’s bloodline under strict control, and Korvus had spent years imprisoned, after his family being killed and him spending his childhood as a slave.

Korvus swept through the X-Men, providing a distraction which allowed Xavier to be taken by other Shi’ar. When he faced Rachel, however, their minds were involuntarily linked when she touched the Blade, due to their links to the Phoenix Force, and a part of the Force residing in the Blade transferred to Rachel. She then telekinetically disabled the explosive implant the Chancellor had had placed in Korvus to force his obedience. Freed, Korvus joined the X-Men in their quest to rescue Xavier and stop Vulcan, and he and Rachel soon discovered a mutual attraction, probably fostered by their Phoenix-empowered connection. Joining up with the Starjammers and the now deposed Lilandra, the X-Men caught up with their prey at the coronation of the reawakened D‘Ken, where they discovered Vulcan was now married to D‘Ken’s sister, Deathbird, and Xavier was about to be sacrificed to the M‘Kraan Crystal. They attacked the gathering, but not in time to stop Xavier being shoved into the crystal. He was rescued, and returned with his mental powers restored. During the battle Vulcan killed D‘Ken, proclaiming himself Emperor, and then killed the Starjammer Corsair, his own father and Rachel’s grandfather. When Xavier was rescued and taken back to their ship, Lilandra locked its controls to take Xavier and the X-Men and Starjammers aboard at the time back to Earth, before returning herself to the battle. The battle ended inconclusively, and Rachel was stranded far from home.

Following Corsair’s funeral, Rachel, Korvus, Havok and Polaris joined the remaining Starjammers, Raza and Ch‘od, and they dedicated themselves to removing Vulcan from power, aiding Lilandra in building her forces and in striking against the Empire’s forces. Rachel learned from Lilandra that a secret order within the Empire had been responsible for the execution of her family. When the Starjammers launched an attack on the strategically valuable, but unexpected, Feather’s Edge, they were surprised when Vulcan’s forces, warned ahead of time, ambushed them. The battle was interrupted when Vulcan’s flagship is destroyed by a third force, the Scy’ar Tal, whose name translateed as ’Death to the Shi’ar‘. Vulcan and Gladiator survived their ship’s destruction, and attacked the leader of the Scy’ar Tal, only to be easily dispatched. The Starjammers attempted to make peaceful contact with the Scy’ar Tal, but were rebuffed, and soon recognised the Scy’ar Tal as the greater threat, when they unleashed their main weapon, a stargate. Called by a beacon dropped on Feather’s Edge, the stargate opened up, dropping a star onto the planet, destroying it, its colony, and the ships which didn’t manage to escape in time. From contact with their leader, Rachel learned that the Scy’ar Tal were originally called the M‘Kraan, and claimed the world of the M‘Kraan Crystal, a holy site for the Shi’ar, had originally been theirs before the Shi’ar drove them off.Seeing the Scy’ar as the main threat, the Starjammers reluctantly accept the offer of a truce with Vulcan, to take out Finality, the Scy’ar’s stargate weapon. At the meeting to discuss strategy, though, Rachel flew into a rage when the Chancellor arrived with his Guards, the Death Commandoes who murdered her family, and she learned that Chancellor Akari had signed the death warrant. She was calmed down by her teammates, and convinced to suppress her rage long enough to work with them against the Scy’ar Tal.

Rachel was part of the small group which attacked the Finality station, while most of the fleet protected the M‘Kraan world. She was stationed aboard the Starjammer, helping fight the Scy’ar Tal forces alongside the Imperial Guard, while Havok and Vulcan boarded Finality itself. After the pair had dealt with the Scy’ar Tal Eldest, Vulcan turned on Havok, and the Imperial Guard attacked the Starjammers. Rachel had to leave the battle when Vulcan fired one of Finality’s beacons through a wormhole towards M‘Kraan. She and Korvus followed it through, and she’d nearly stopped it when Gladiator intercepted her. Urging Korvus on after the beacon, she faced Gladiator in combat, going toe-to-toe with him. When Korvus’s craft was blown up by a shot from a previously friendly ship, most of which chose to rejoin the Empire with Vulcan’s victory, she forced Gladiator aside and rushed to Korvus’ side, too late to stop the beacon, but in time to get them out of there. They joined up with the fleeing Lilandra, but the other Starjammers were Vulcan’s prisoners. The three continue their resistance against the Empire.

In her weakened state she was taken in by Spiral who offered to remake her as she wanted to be, but actually took her to Mojoworld, where she became prisoner of Mojo. She eventually managed to escape, travelling the dimensions hunted by Mojo's Death Commandoes were captured, and turned over to the authorities.