The Brotherhood of Mutants is a group dedicated to the cause of mutant superiority over humans. Throughout its various incarnations, the Brotherhood's agenda has gravitated towards either subjugating the human race to the will of mutants or eradicating humanity altogether. Magneto formed the Brotherhood of Evil Mutants, including Astra, Toad, Quicksilver, Scarlet Witch, and Mastermind, shortly after the public debut of the X-Men. After a falling out with Astra that led to her quitting the team, Magneto had the Brotherhood initiate an attack upon humans that was thwarted by the X-Men. Magneto then attempted to recruit the thunder god Thor into his Brotherhood, but Thor refused. The Blob was the next candidate for recruitment, but ultimately declined to join after seeing the way Magneto mistreated his followers. Mastermind then sought to recruit Unus the Untouchable; however, he was blackmailed by the X-Men into declining the offer in exchange for reversing his then-amplified powers. During an encounter with the enigmatic Stranger, Magneto and the Toad were captured and taken to the Stranger's homeworld, shortly after which Quicksilver and the Scarlet Witch joined a revamped version of the Avengers led by Captain America.

After witnessing the brutal murder of his family by the Nazis, Max Eisenhardt, was sent to the Auschwitz death camp where he served in the Sonderkommando, the squad of Jewish men forced to helped their Nazi masters operate the gas chambers, ovens, and fire pits of the camp. While in Auschwitz, Max met a gypsy girl named Magda. Max and Magda survived the Holocaust, and later were married. They had a daughter, Anya. Max first consciously used his mutant powers when his family was trapped in a burning house. Unable to rescue his daughter from the blaze due to his inexperience, coupled with interference from a hostile mob, he angrily unleashed his powers to vengefully slaughter the humans. Terrified, Magda left him, and months later discovered that she was pregnant. Magda presumably died after giving birth to mutant twins at Wundagore Mountain. To shake off his pursuers, Max had master forger George Odekirk create the identity of Sinte gypsy “Erik Magnus Lehnsherr.” Max eventually made his way to Israel where he worked as an orderly in a psychiatric hospital near Haifa. He befriended Charles Xavier, with whom he shared lengthy debates, hypothesizing what would happen if humanity were to be faced with a race of super-powered beings. The pair ultimately revealed their true natures to each other when they prevented Nazi war criminal Baron Wolfgang von Strucker from obtaining a large cache of Nazi gold. Causing a cave-in that seemingly killed Strucker, Max realized that his and Xavier’s views on mutant/human relations were incompatible and left with the gold. Fearing another Holocaust, he took an aggressive and lethal stance against humanity. Max has often expressed the belief that mutants, whom he calls Homo sapiens superior, will eventually be the dominant life form on the planet, and has wavered between wanting to exist in harmony with humans, wanting a separate homeland for mutants, and wanting to enforce his superiority over all humanity.

Calling himself Magneto, Max banded together a group he dubbed the Brotherhood of Mutants, later referred to as “Evil” by the media. Among the assembled members were his children, now the mutants Quicksilver and the Scarlet Witch. Magneto soon found himself opposed by Xavier and his own group, the X-Men. After a battle against the X-Men and the Avengers, Magneto was presumed dead, but managed to survive by using his powers to burrow through the ocean floor into a series of caverns that led him to the secluded Antarctic prehistoric jungle of the Savage Land. There, he used his knowledge of genetic engineering to mutate local savages into super-powered beings he dubbed the Savage Land Mutates. Soon after, Magneto was again opposed by the X-Men, and was once more presumed killed in an explosion. Yet again, Magneto survived, finding himself in the Savage Land city known as the “Land of the Dead” where he discovered a mind-numbing gas that he intended to use against mankind. He projected his astral self to the native peoples, manipulating them into building an airship filled with the gas. His plan was once again foiled by the X-Men, and he fled into the ocean. Rescued by the Mutate Amphibius, Magneto was taken to an island, where Sauron was working on a machine to tap the geothermal energies of the region. Magneto realized that the device could help restore his ailing powers, but was once again opposed by the X-Men and believed dead.

Mutants! The very word strikes fear and worry in many people's hearts, but many also dream of a peaceful coexistence between man and mutant. Professor X had such a dream, and his X-Men is a team of mutants willing to take stand for it!

Born of the void between states of being, the Phoenix Force is a child of the universe. In the dying moments of the previous universe, the Force saved all existence from eternal damnation, enabling Eternity to preserve the humanoid Galan, ensuring his re-creation as Galactus. The Force was subsequently reborn from the cosmic fires of the “Big Bang.” Later, it encountered the malevolent Le Bete Noir and trapped it in the center of a still-cooling planet Earth. The Force was drawn back to Earth when it was awakened to reality by Feron, a sorcerer from an alternate Earth who had traveled with his master Necrom to a tower on Earth-616 to witness an alignment of dimensional interfaces. The Force joined with Feron, allowing itself to be shaped by his dreams into the form of a giant fiery bird and experiencing a spectrum of new sensations. At the moment of the alignment, Feron bade the Force to project the essence of the tower throughout the multiverse, so that it existed on every plane of reality simultaneously, creating an energy matrix. Necrom sought to access the matrix to allow him to compress all alternate Earths into a singularity, the energy released from which would endow him with godlike power, and to that end he tore out the portion of the Force that had bonded to Feron. In agonized confusion over the violation of its essence, the Force fled. Necrom bound the stolen Force with a portion of his own essence, and left it to incubate in a corpse he dubbed the Anti-Phoenix.

By somehow obtaining a sample of Jean Grey's cells. Mister Sinister created an adult clone of her. When the original Phoenix committed suicide, Scott believed he had lost Jean forever, unaware that her original body lay in suspended animation in a pod at the bottom of the sea. Sinister grew his clone at an accelerated rate in his laboratory. He named her "Madelyne Pryor" and programmed her with false memories and the desire to fall in love with Cyclops. When Phoenix died, its share of the real Jean's consciousness traveled back to Earth. This part of Jean's psyche eventually reached the clone that Sinister had created and endowed it with consciousness for the first time. Sinister then planned for Madelyne to bear a child, which would possess the superhuman genetic potential of both Scott and Jean. The evil mutant would then capture the child and control him as he grew up. Scott Summers first met Madelyne Pryor in Alaska, where she was working as a pilot for North Star Airways, the company run by his grandparents. Scott and Madelyne were married when he became convinced that she was not Jean Grey, Madelyne's exact lookalike. The scheme started successfully: Cyclops married Madelyne, and they had a son, Nathan, who was destined to become Cable.

Following Professor X's arrest for crimes committed as the evil psionic entity Onslaught, Scott assumed the role of leadership of the X-Men once more. Soon after, the government sponsored mutant-hunting operation known as "Zero Tolerance" took effect, and the villainous Bastion captured the X-Men. In his attempt to destroy mutantkind, Bastion placed a nanotech bomb inside Scott's body. The X-Men escaped, and the mutant doctor named Cecilia Reyes saved Scott's life. Scott and his wife soon took a leave of absence from the X-Men for a period of recuperation.

Not long after returning to the team, Scott and Jean soon found themselves embroiled in Apocalypse's bid for cosmic power by assembling "The Twelve" - a group of mutants who would determine the fate of their kind that included Scott, Jean, and Cable. They were wired to a machine that would channel their awesome energies into Apocalypse, allowing him to absorb the body of the time-tossed powerful mutant teenager known as X-Man. As his teammates fell around him, a powerless Scott saved X-Man and merged with the would-be conqueror to create a new evil entity. Jean detected Scott's psyche inside Apocalypse and prevented the X-Men from destroying him, however he was presumed dead by most of his teammates. Only Jean and Cable refused to believe Scott had perished. Investigating rumors he was alive, the pair found him in the birthplace of Apocalypse in Akkaba, Egypt, struggling to reassert his mind over the villain's psyche. Ultimately, Jean was able to physically rip Apocalypse's essence from Scott's body using her mental powers, and Cable destroyed it with his own powers.

Scott Summers was the first of two sons born to Major Christopher Summers, a test pilot for the U.S. Air Force, and his wife Katherine. Christopher was flying his family home from vacation when their plane was attacked by a spacecraft from the interstellar Shi'ar Empire. To save their lives, Katherine pushed Scott and his brother Alex out of the plane with the only available parachute. Scott suffered a head injury upon landing, thus forever preventing him from controlling his mutant power by himself.

With their parents presumed dead, the authorities separated the two boys. Alex was adopted, but Scott remained comatose in a hospital for a year. On recovering, he was placed in an orphanage in Omaha, Nebraska that was secretly controlled by his future enemy, the evil geneticist Mister Sinister.