How does Napoleon change over time?
Napoleon, based on Joseph Stalin, has a desire for power from early on, but grows more corrupt and less like an animal as he becomes more powerful. At first, this "rather fierce-looking Berkshire boar" is considered to have "depth of character," though what kind of character is not specified. At first too, Napoleon treats the other animals generously, giving them double food rations after they run Mr. Jones off the farm. Later, he surrounds himself with fierce dogs and cuts the other animal's rations in half if they don't work extra hours. Despite the commandment that decrees that all animals are equal, he sets himself above the others.
Increasingly, Napoleon breaks the animal code, ultimately breaking all seven of the Seven Commandments. He moves into a house and sleeps in a bed. He institutes a reign of terror, killing animals who oppose him By the end of the novel, he is walking on two legs, wearing human clothing and drinking alcohol. In fact, he can't be distinguished from a human.