When Callisto was young and beautiful, her life seemed so perfect, so enviable. But catastrophe struck her, as she learned that living as a mutant would not be easy. She was blinded in the right eye and was left horribly disfigured. Forced to hold up a mirror to her new reality, Callisto realized that society had little use for a mutant, especially one who was beautiful no more. Scared and alone, she rebelled against society and decided to go underground where it was safe and where she could escape prying, peering eyes. She quickly made a huge abandoned military tunnel called "the Alley" built underneath Manhattan in the 1950s her home.
With help from the mutant-detecting Caliban, the devoted Sunder, and the treacherous Masque, she organized a community of mutant outcasts called the Morlocks who lived in the Alley. Unknown to Callisto, the Morlocks' existence was orchestrated by the extradimensional sadist called the Dark Beast, a twisted alternate version of Hank McCoy.
In recent years, Callisto, apparently driven to irrationality by her responsibilities, abducted the winged Angel as a consort. Angel's X-Men teammates invaded the Alley but were captured as well. The team's leader, Storm (Ororo Munroe), challenged Callisto to trial by combat, almost killing her and winning the mantle of Morlock leader.
Over time, the ties between the X-Men and the Morlocks grew closer, the two teams constantly confronted and helped each other. Callisto's rivalry with Storm was changed as they teamed up to fight against Kulan Gath. Initially hating Storm, Callisto, the de facto leader in Storm’s absence, grew to respect Ororo and the X-Men. The Morlocks and the X-Men worked out an even higher sense of mutual respect when the X-Men founder, Professor X, had his life saved by Callisto after a beating by anti-mutant protesters.
Callisto and her growing band of outcasts became the victims of a massacre, orchestrated by Mister Sinister and implemented by his team of Marauders. The few survivors, including Callisto, were treated by Moira MacTaggart on Muir Island, Scotland; in gratitude, Callisto appointed herself MacTaggart's bodyguard and assisted Cyclops against the mutant-hating Master Mold.
However, she was captured by Masque, who had, via the young telepath Brain Cell, enslaved the remaining Morlocks. To taunt her, Masque restored Callisto's long-lost beauty, controlled her through Bliss's powers, then freed her in New York City, forging a super-model career for her to torment her. However, the former X-Man Colossus, without his memories, helped Callisto to get free from Masque. Shortly after, Callisto and Colossus parted ways when the Shadow King psychically manipulated Colossus into becoming one of his slaves.
When Masque was believed dead, the remaining Morlocks went mad and attacked Callisto, demanding her to come back as their leader. Callisto and her fellow Morlock, Healer, escaped alive, though severely injured, and sought the X-Men’s aid. At the X-Mansion, the Healer used his last forces to heal Callisto, sacrificing himself, the process was successful, but returned Callisto to her scarred appearance. Mikhail Rasputin, Colossus's brother, convinced Callisto to join him in destroying the Morlock Tunnels and killing themselves and the remaining Morlocks. However, Mikhail managed to transport himself, Callisto and the Morlocks to the Hill, a dimension of rapid time passage. There the survivors, including Callisto, built a new society based on survival of the strongest. The younger generation escaped to Earth as the terrorist unit Gene Nation. Callisto followed the Gene Nation back to Earth and again recruited the X-Men to stop her wayward charges, whom she later tried to rehabilitate in the Alley.
When the government anti-mutant persecution increased, Callisto and her prot�g� Marrow attacked official Henry Gyrich but were held off by Spider-Man, who in turn helped them battle Prime Sentinels. Severely wounded, Callisto was cared for by Marrow, who had become an X-Men. Callisto frequently insisted that Marrow should take hold of this opportunity and be in peace with the X-Men, she would even team up again with her longtime rival, Storm, to help Marrow adjust to her new life. Callisto was finally cured, by the efforts of the Dark Beast, who had plans for both her and Marrow concerning the X-Men.
