Kurt Busiek

The second Busiek/Pérez Avengers omnibus contains the arc most frequently cited as the definitive Avengers story: Ultron Unlimited, the four-issue siege of an Eastern European nation where Ultron kills every living being and constructs an army from their remains. Busiek spent the preceding issues building Ultron's return to maximum dread, and when the assault arrives, Pérez's artwork of the Avengers standing against an enemy that has already won is among the most powerful in the character's history.