Dr. Henry Jonathan "Hank" Pym is a character appearing in American comic books published by Marvel Comics. Created by penciller Jack Kirby, editor-plotter Stan Lee and writer Larry Lieber, Pym debuted in Tales to Astonish #27. He returned several issues later as the original iteration of Ant-Man, a superhero with the power to shrink to the size of an ant. He later assumed other superhero identities, including the size-changing Giant-Man and Goliath; the insect-themed Yellowjacket; and briefly, the Wasp. He is a founding member of the Avengers superhero team, and the creator of the robotic villain Ultron. He is also the ex-husband of Janet van Dyne and the father of Nadia van Dyne, his daughter by his first wife, Maria Pym.

Ultron is a supervillain appearing in American comic books published by Marvel Comics. Created by writer Roy Thomas and artist John Buscema, the character first appeared as an unnamed character in The Avengers #54, with his first full appearance in The Avengers #55. He is a self-aware and highly intelligent artificial intelligence in a robot body who develops a god complex and a grudge against his creator Hank Pym. His goal to destroy humanity in a shortsighted attempt at creating world peace has brought him into repeated conflict with the Avengers. Stories often end in Ultron's apparent destruction, only for the character to be resurrected in new forms.