Little is known about Erik Lensherr's childhood before the year 1941 but it's believed he came from a professional and educated Jewish family in the East Prussia area of Poland until when Nazi Germany took over. His family was moved to the Warsaw Ghetto then transferred to Auschwitz death camp in 1941. The 13 year-old's latent powers saved him from the bullets that gunned down his parents, sister, and other Jews.
Erik was then found by Nazi guards and presumed to be older than he was. After months of untold abuse, the 14 year old then became a 'Sonderkommando' or a scavenger for the gold and other items of wealth found on corpses of his own people. Erik kept his humanity however and became more of a protector to the weaker people in the camps. During this time he met and befriended a young gypsy named Magda and helped her to escape the same fate her parents had suffered. She was the only one willing to go with Erik to escape Auschwitz in 1945 despite her frailty.
Three years after their escape and dealing with conflicting emotions of the past and their attraction towards each other, Erik and Magda marry and live in a Carpathian village. In 1950 Magda gave birth to the couple's first child, Anya, who was certainly her father's child. While Magda was happy with her simple life, Erik wanted to enter a university and provide his wife and daughter.
In 1955 Erik moved his family to the city of Vinnitsa located in the Soviet Union. The first week the family lived in Vinnitsa Erik was cheated out of his pay and accused his foreman and then attacked him. Later that day the foreman leads a riot that sets near the inn where Magda and Anya are staying, the riot leads to a fire resulting in killing Anya and Magda. Erik in a fit of rage, releases his first electro magnetic radiation blast before collapsing on the spot where the KGB find him hours later. He was arrested and later sentenced to life to serve in Siberia.
Too stubborn to die but with nothing to live for, Erik manages to survive the harsh Siberian workloads and winters yet he does not attempt to escape. However he works on contorling his powers, unaware he's being watched. During his third year in Siberia the age of 30, Erik was then transported to Moscow to be the first experimentation of the USSR's Super Human project. However the experiments fail due to Erik's stubbornness to go along and his already mutated genetics. Feared to be too powerful Erik was placed in cryogenic sleep. In 1977 he was released from sleep for another extermination but managed to escape to Israel under an assumed name, Erik Magnus.
For six years 'Magnus' worked at a local hospital, went to a Tel Aviv University where he later met Doctor Isabelle Stien and the two had a brief affair, and broke up in 1983. A few months later Isabelle gave birth to twins and gave them up for adoption to a wealthy Transiaian Maximoff family. When Magnus met Isabelle a few years later in 1985 and they became friends again.
In 1985 then Magnus meets a visiting American psychologist named Charles Xavier and befriends him. They find out they're both mutants and due to slowly rising hostility towards mutants decide to create a safe haven. Both seek out areas to start this Utopia until Xavier stumbles upon an area known as the Savageland. Isabelle supports their ideology and sets up a clinic for mutants only. In the Savageland things ran smoothly but tensions between the beliefs of Xavier and Magnus grew higher as anti-mutant terrorism outside of the US grew stronger. In 1987 an anti-mutant terrorist group set off a bomb in Israel near in Isabelle's clinic, killing her a few dozen mutants.
This was enough to finally push Magnus over the edge, he wanted mutants to rule and to enslave the humans before mutants are wiped out. Xavier was more hopeful and assured that a peaceful coexistence could happen between the two races. They have a falling out; Xavier leaves the Savage Land and returns to the Xavier Mansion, Magnus then prepared to start his battle with humanity.
He found allies and troubled young mutants to recruit to his battle and found out about his twin children going over papers about Isabelle. Magnus stole his childern back a few months after the fall out with Xavier. Wanda got along with her father yet Pietro, despite his eagerness, was placed at a distance and faced his father's ridicule.
In 2000, Magnus dubbed himself Magneto and declared war with the blissfully unaware America who ignored the anti-mutant attacks outside of the US as they did with the Jews in WWII.