Ultron-13 was the thirteenth incarnation of Ultron, constructed by Doctor Doom to use against Daredevil during the Acts of Vengeance. Doom incorporated the personalities of all 12 prior Ultron versions into 13's personality. He increased the influence of the kinder Ultron-12 to curb the destructive impulses of the other personas, but the result was a mentally unstable Ultron with a multiple personality disorder. Ultron-13 engaged in various erratic behaviors, such as constructing a hundred or so Ultron heads, and becoming attracted to the genetically altered woman known as Number Nine. The robot was soon engaged by Daredevil and the Inhuman Gorgon and Karnak. Despite his power, the deranged Ultron-13 suffered defeat.
He later stabilized into one coherent personality, and embarked on a campaign to convert California's human population into robotic life. This attempt was narrowly stopped by the West Coast Avengers, but Ultron escaped before he could be imprisoned. He next attacked Empire State University in an attempt to steal a synthetic vibranium known as Nuform. Ultron-13 was defeated by Spider-Man, Iron Man, the Black Panther, and the Sunturion. Ultron apparently proceeded to upgrade to Ultron-14 after this failure.