A duplicate Ultron body that was defeated by the West Coast Avengers was left for scrap in a junkyard in Los Angeles. The head of this duplicate managed to maintain an active CPU despite being separated from its body. This head was later discovered by a petty criminal named Marianella Mancha, who believed it to be an oracle of sorts. Ultron proceeded to assemble a new body for himself with the help of Marianella, and then used DNA samples from Marianella to grow a "son" that was part machine and part man. Ultron aged this subject to the false appearance of being roughly 16 years old, though it was actually only a few years old. He named this creation Victor and left him in the care of Marianella with dormant programming preparing him for his first contact with super-powered beings on a planned trip to New York at age 18.
Marianella kept Victor isolated on the West Coast so that he would not make contact with any super-beings, who were concentrated on the East Coast. Victor was a student at East Angeles High School in Los Angeles when he first met the Runaways. Ultron, still wishing to keep Victor's true origin a secret, sent a Doombot to kidnap Marianella and pose as Victor's father. Victor and the Runaways rushed to rescue her and the Doombot was destroyed; Ultron chose that moment to reveal himself and killed Marianella right in front of Victor. Ultron then triggered Victor's sleeper-switch so that he would attack the other Runaways; however, Gert was able to reason with Victor and he rejected his programming, defying his "father". Afterwards, the Runaways took the now-orphaned Victor back to their hideout to keep him from ending up in Social Services.
Because of his superior intelligence and electromagnetic powers, Chase nicknamed him the Calculator Kid and Nico called him Zapper. After observing the team in action for a month, Victor proved his worth by defeating Swarm using his electromagnetic abilities.
Presently, the Runaways are mostly friendly towards Victor, but they know that he is still a potential threat. He is often paired with Molly Hayes when the team separates to buy supplies, because Molly is the only individual member of the team strong enough to take him down should he go rogue. Chase Stein is still suspicious of Victor, and resents his developing interest in Gert. Judging by a comment made by Nico Minoru, she is fully prepared to kill Victor if the need arises.