Antagonist

Those pigs

Those pigs are pretty antagonizing, but especially Snowball and Napoleon. They begin as animals, members of the working class under the control of the humans, but quickly step up to a position of leadership after the Rebellion. They just get more antagonist-like after that: stealing food, abusing the animals, and ultimately becoming indistinguishable from the oppressive humans they once fought to overthrow. The pigs are corrupted by the power they seize; they do not begin as antagonists (think old Major – not a dislikable dude!), but rather become antagonists as the story develops.