9. The supervillain Ultron became the arch nemesis of which group in the Marvel Comic Universe?
From Quiz I Saw 'U' in the Comics
Answer:
The Avengers
With the popularity of the Marvel Cinematic Universe, where Ultron first made an appearance in "The Avengers: Age of Ultron" (2015), it is easy to overlook that Ultron had been around for almost fifty years prior. He made his first appearance in "The Avengers" #54, which was published in July 1968. At that point, he was an unnamed character but got his first true gig in the next edition (August, 1968).
Unlike the movie, in the comic realm, he was created by Hank Pym, who patterned Ultron's thought processes on his own brain symmetry. Eventually Ultron became self-aware and rebelled against Pym. The rebellion soon turned to hatred. He would go through a process of rebuilding to make himself faster, stronger and much more powerful. He eventually brainwashes Pym into forgetting that he even existed, and then sets about creating Vision, a synthetic form of himself, to use as a weapon to try and destroy the Avengers.
Ultron is notable for being the first character in the Marvel Universe to use the fictional alloy adamantium.