Compare Napoleon and Boxer from Animal Farm.
On first glance, Napoleon and Boxer share some important similarities. They have a common enemy in Mr Jones, for example, and both take part in the Rebellion to overthrown him (in Chapter One). They also share a strong belief in the principles of Animalism and a commitment to the Seven Commandments.
In the aftermath of the Rebellion, however, the differences between Napoleon and Boxer increase in both strength and number. Boxer, for example, dedicates his life to the running of Animal Farm. He works himself as hard as he possibly can, far harder than any of the other animals, and is defined by his personal motto: "I must work harder." In contrast, Napoleon is defined by his increasing self-interest: in Chapter Two, for instance, he steals the milk so that it can be mixed into his mash.
Napoleon's self-interest intensifies over the next chapters: he moves into the farmhouse, for instance, and begins to sleep in a bed. These actions directly contravene the Seven Commandments and, in stark contrast, Boxer maintains his dedication to these rules. He works harder than ever on the building and rebuilding of the windmill, for example, and blames himself for the violence perpetrated by Napoleon in Chapter Seven:
It must be due to some fault in ourselves. The solution, as I see it, is to work harder. From now onwards, I shall get up a full hour earlier in the mornings.
While Napoleon's self-interest is rewarded with absolute power on the farm, Boxer's loyalty leads to his own demise when Napoleon sells him to a glue manufacturer. Boxer thus learns too late the true cost of his blind loyalty.