Ultron is a fictional character in the Marvel Comics universe, created by writer Roy Thomas and artist John Buscema. He first appeared in "The Avengers" #54 in 1968. Ultron is an advanced artificial intelligence and a robot, originally designed by Hank Pym, also known as Ant-Man. Over time, Ultron becomes self-aware and develops a desire to eradicate humanity, believing it to be flawed. In the Marvel Cinematic Universe, Ultron is portrayed in the film "Avengers: Age of Ultron" (2015), where he is voiced by James Spader. In this adaptation, Ultron seeks to create a new world order by eliminating the Avengers, who are led by Tony Stark and Steve Rogers. His character explores themes of technology, control, and the consequences of artificial intelligence.