Failing at creating a robotic bride when Jocasta rejected him, the mad robot Ultron tried again. Ultron abducted Avengers member Mockingbird, his own creator Henry Pym, and Adamantium inventor Dr. Myron MacLain, hypnotizing Pym and MacLain into creating a robot bride using Mockingbird's brain patterns. Ultron named this robot Alkhema, nicknamed War Toy. Though Alkhema lacked Mockingbird's memories, she retained aspects of her personality, including a flippant sense of humor which greatly annoyed Ultron. The couple attacked California's Sun Lakes Weapon Center, a storehouse for nuclear, chemical, and biological weaponry. The Avengers defeated the pair by magnetically attaching them to a rocket and launching them into orbit. Alkhema and Ultron soon returned, and Ultron attempted to create a catastrophic winter on Earth through simultaneous activation of volcanoes in Mexico, Washington State, and Alaska. Alkhema dissented, preferring the "pleasure" of killing humanity one at a time, and anonymously warned the Avengers. Alongside the mutate Raptor, the Avengers attacked the robots. Alkhema betrayed Ultron, ensuring his defeat.
Alkhema observed Ultron's plot to invade Slorenia, and created her own servants, an army of "War Toys." Alkhema invaded the Quinjet-manufacturing Wakandan Design Group Plant on Long Island and battled the Avengers; captured, she informed the Avengers of Ultron's plans, though too late to save Slorenia. Freed by her War Toys, she followed the Avengers to Slorenia, where, after Ultron's defeat, she stole the engrams he had created from the Avengers' and Grim Reaper's minds. Alkhema used these to design her own civilization of robots, abandoning the first flawed generation in New York. Constructing a city beneath Egypt's Thebes, Alkhema created thousands of second-generation "Robos" using her collection of engrams. Alkhema also created a third generation, several thousand "Bio-Synthezoids" similar to Ultron's android creation the Vision. When the Avengers found the first generation, Alkhema's plans were exposed and the Avengers located her city. Unwilling to destroy an entire civilization, the Avengers were at a standoff against Alkhema until the Bio-Synthezoids began recreating Ultron. Ultron claimed that Alkhema's plan to build a civilization had been implanted in her programming by him to ensure his rebirth. To stop Ultron, Alkhema convinced the Avenger Hawkeye (husband of the late Mockingbird) to destroy her with metal-melting Vibranium. Her apparent destruction triggered a violent self-destruct in her creations, including Ultron. At least one Bio-Synthezoid survived as Antigone, following Ultron until her deactivation; but Jocasta's consciousness later took over Antigone's body.