In the Age of Apocalypse, Lorna remained with her adoptive parents and didn’t manifest her magnetic powers until Apocalypse started culling the human population of Northern America. The traumatic experience of her parents being killed right next to her caused Lorna to become somewhat insane. Because of having similar powers, she was totally convinced that Magneto had to be her true father. For a time, she formed some partnership with Rogue, another confused mutant, until one day Rogue accidentally absorbed half of Polaris’ magnetic powers. While Rogue eventually joined the X-Men, Lorna ended up in the breeding pens of Mr. Sinister and the Dark Beast. Apparently, their genetic scans proved Lorna’s claim of being Magneto’s daughter wrong, though in her deranged state she continued to believe in him as her father and was convinced that he would come to save her. Later, she was indeed was liberated from the pens by Prelate Scott Summers, who took pity in her, as his brother Havok tortured her for information on recent breakouts. In her delusional state, Polaris believed that Scott was her father Magneto.
Note: Despite the genetic scans confirming that she was not Magneto's daughter it's important to take into account the source. The Dark Beast and his master Mr Sinister were hardly what you would call reliable narrators. Mr Sinister had been actively plotting the assassination of his Apocalypse. A fact that the Dark Beast was fully aware of. Hiding the daughter of the second most powerful man on that world, Magneto made tactical sense. Had Sinister's plan been successful Polaris would have been a valuable bargaining chip to ensure either man's survival against the master of magnetism.
The Polaris counterpart of the Mutant X universe was happily united with her father, Magneto, who had denounced his criminal ways and was leading the X-Men. In this reality, Lorna and Alex never had a relationship. Quite on the opposite, there seemed to have been some bad blood between them, for Polaris was angry at Havok for leaving the X-Men and taking several members with him to start a rival group - the Six, out of disagreement with Magneto. Circumstances later forced the two groups to work together again. To fight the combined threats of the Beyonder, Dracula and the Goblin Force, most of this reality’s heroes gathered together for a big fight. Polaris was just one of numerous casualties. She died in her father’s arms, who gave her as much comfort as possible.
In the alternate future timeline known as Earth X universe, every human being on Earth gained superpowers when the Inhumans’ Terrigen Mists was released into the atmosphere. No longer needed as heroes, and not liking the many changes on Earth, Havok and Polaris accepted Corsair’s invitation to join them in outer space, aboard the Starjammer. They often asked Cyclops to join them as well, but time and again he refused, having found himself a new purpose in training another team of outcasts.
The reality-hopping Exiles met a rather unique version of Lorna during their travels. This Polaris had not only joined the Avengers in this timeline, but the entire group had been turned into vampires at one point, and they were no longer using their abilities to do heroic deeds. Although the Exiles’ mission didn’t necessarily involve killing the vampires, they had hardly much choice, as the Avengers were ready to fight to the death. Polaris was killed when Magik rammed a wooden stake through her heart. [Exiles #31] Albeit her costume was almost identical to the one worn by the Mutant X version, there seems to be no connection between the two timelines; there are hardly any similarities.
In the Ultimate Universe, Polaris was on the short list of candidates for the government-sponsored mutant team gathered by Emma Frost. 
However, the president didn't want her in the group, due to people still being nervous about mutants with magnetic powers after Magneto's attack. When that short-lived team came to an end, though, Lorna was convinced by her boyfriend Havok to enroll at the Academy of Tomorrow, an institute where Emma trained her students to become ambassadors for mutantkind rather then soldiers. That didn’t stop the mutants from embarking on missions behind Emma’s back, though, and during one such occasion, Lorna lost control over her powers, with everything made of metal close by being hurled around. A few lives were lost and Polaris begged Havok to kill her, but she was only rendered unconscious and taken to the same prison that Magneto was in. Both the X-Men and the students of Academy of Tomorrow tried to rescue her, while Magneto was trying to lure her to his side. Lorna saw through the manipulation and challenged Magneto. He broke out and escaped, but Polaris was cleared of all crimes as it was revealed that Magneto’s lackeys had used technological equipment to cause Polaris’ powers to spiral out of control. She then returned to the Academy of Tomorrow with Havok. Unfortunately depsite all of her potential, Polaris' life was brief. She was later murdered along with many of her classmates when Magneto had one of his lieutenants bomb the Academy of Tomorrow during the Ultimatum event. Her corpse was then recovered by the suriving X-Men and she along with her classmates were buried along with the dead X-Men in Westchester.
Ten to fifteen years in the future, the X-Men met their End when several of the X-Men’s opponents banded together and attacked the team simultaneously on various fronts and from all sides. Polaris was still a mainstay of the team and, despite being about twenty years older than him, 
romantically involved with “Kid” Colossus, the son of the late X-Man with the same codename. When it was discovered that Cassandra Nova, the mastermind behind the attacks, was residing in Shi’ar space, Polaris and Magneto used their powers in combination to create a wormhole big enough to transport the assembled X-Men and their allies to Chandilar. However, one of the Shi’ar Imperial Guard attacked right then, absorbing the life-forces of father and daughter causing an energy feedback. After they averted the imminent explosion, the X-Men discovered that in death Magneto was channeling the planetary magnetic field of Chandilar sustaining both his own and Lorna’s body as coherent energy manifestations, allowing them to live on for a few minutes. After she helped to re-establish the needed wormhole, Polaris finally died in the arms of her former lover, Iceman.
In the re-shaped reality of the House of M, the Scarlet Witch had tried to give everyone their heart’s desire. Lorna’s wish to belong somewhere and to find acceptance meshed well with Magneto’s dreams. In the new world order, mutants were the ruling class, with Magneto being their monarch. Residing with him in his palace on Genosha were all his children. Polaris, Quicksilver and the Scarlet Witch were considered royalty in this reality, and Lorna had a close relationship with her father. Her origin in this world was substantially changed. She had been the product of a relationship between Magneto and a woman named Susanna Dane, an American art student living in Paris. This Lorna was raised by her mother who died of a prolonged battle with cancer. Bizarrely Lorna's mother in this reality looked nothing like her biological mother.
The Polaris of X-Men Forever life seemed to be the same up until the point she joined X-Factor and the timeline diverged from 616. Her relationship with Havok was very solid in this world. Despite being a member of X-Factor she was rarely seem among them preferring to spend time with Havok’s family. On several occasions she along with the Starjammers she teamed up with the core X-Men team against threats such as the Imperial Guard and the Marauders. Unfortunately for Polaris, she and Havok also went with the X-Men on their mission to Havok’s old stomping grounds, in Genosha to battle an evil clone of Storm who had conquered Wakanda and was attempting to annex the ravaged country. The mission turned into a tragedy when the Storm clone killed Havok. Polaris was infuriated with the death of her love and attempted to kill the clone but the real Storm was able to convince her though that X-Men don’t kill. In the aftermath of the battle, Polaris was offered the role of chief magistrate however at that juncture she was unsure if she take up the offer. Havok might have loved Genosha but she wasn’t sure if she could.
Two alternate versions of Polaris had the odd privilege of meeting each other. The Polaris or Earth 8149 was battling the mutant hunting sentinels in her world when she was seemingly overwhelmed and killed. In reality or rather another reality, she was plucked out of the time stream by the Exiles to serve as new member of the group. Polaris first mission was to journey to a world alongside a group of heroes, including an alternate version of her sister Scarlet Witch and veteran Exile, Blink although Blink pretended she had been plucked from reality in the same manner as the rest of the new team. The fledgling group's first mission was destabilize the mutant monarchy of another reality. In that reality Magneto had become king of the mutants, after the death of Charles Xavier. Although Magneto himself did not kill Xavier he did not prevent his death. After Xavier's death, Magneto united the Brotherhood and the X-Men and later the entire mutant race formed a kingdom on Genosha. Magneto's daughters, Polaris and Scarlet Witch lived there as spoiled princess and infamous rivals. The Exiles decide to use their own Polaris and Scarlet Witch to impersonate the princesses and easily incapacitated them. This ruse was short lived as they were soon discovered. The group were later freed and managed to grasp Magneto's helmet off him. Without his helmet, the telepath's of his kingdom read his mind and found out he had let Professor X die. When Jean Grey of this reality found this out she executed Magneto. The group only had one more mission in another reality that had become overcome by machines before having to return to the previous reality. The Exiles had failed to destabilize the mutant government so were forced to come up with a new idea, this time they decide to expose the affair of Cyclops and Emma Frost to Jean Grey.
Both women were very popular among the masses and their battle over their “Helen of Troy”, Scott Summers split the nation. This proved fortuitous as the mutants would have been wiped out by anti-mutant forces had they all remained on Genosha. Ultimately what happened to the Polaris of that world after the fall of the monarchy is unknown. The Exiles version of the Polaris decided to stay with the team even after Blink's duplicity was revealed. She later found that her apparent death had caused her father Magneto to return to the side of the angels and he freed her world from the rule of the Sentinels.