There are two main characters in The Most Dangerous Game. They are: Sanger Rainsford and General Zaroff.
Sanger Rainsford is a big-game hunter of great repute. When the story opens he is traveling by sea, and makes light of his profession:
"The world is made up of two classes -- the hunters and the huntees. Luckily, you and I are hunters."
"...I'm a hunter, not a murderer."
He finds this philosophy challenged by General Zaroff, who agrees with him in a much broader sense: men fall into both categories instead of just one. His moral sense -- that man is not an animal to be hunted -- is repulsed by Zaroff's ideas, and he is forced over three days to reevaluate both his philosophy and his morals. Although he insists several times that hunting man is murder and he will not condone it, he sets traps clearly intended to kill; Rainsford is a pragmatist, but only when he has no choice. By the end of the story, Rainsford takes steps to kill Zaroff; he has other choices, including stealing a boat or freeing Zaroff's slaves and taking him prisoner, but he feels that Zaroff drove him to this position and must be eliminated. It is possible that he becomes interested in the lifestyle itself; the final line:
He had never slept in a better bed, Rainsford decided.
could be either a well-deserved rest or an embrace of the luxury that Zaroff lived in. If it is the latter, the change in his moral philosophy would have undergone an extreme shift.
General Zaroff is both Rainsford's compliment and polar opposite. He is a big-game hunter, a master of woodcraft and tracking, but he is also an aristocrat, a lover of fine wines and good music. He enjoys speaking of writers and poets, and feels that his heritage is as important as his chosen profession. However, he is also an extreme sociopath, with no moral boundaries or qualms. He views humanity as an animal on par with any other, only with the ability to reason instead of acting on instinct.
"Life is for the strong, to be lived by the strong, and, if needs be, taken by the strong. The weak of the world were put here to give the strong pleasure. I am strong. Why should I not use my gift? If I wish to hunt, why should I not?"
"It gives me pleasure. They can reason, after a fashion. So they are dangerous."
During the hunt Zaroff shows his mastery of tracking and manages to avoid every one of Rainsford's traps. His fatal mistake is overconfidence; he allows Rainsford to live no less than three times to extend the hunt. This pursuit of his pleasure over pragmatism -- a trait Rainsford exhibits -- is his downfall. Additionally, he cannot think that Rainsford could be so persistent as to risk death, only to return and risk it again to challenge him.
Rainsford and Zaroff are opposites morally, but in their actions they are more alike than not. Each has a driving need to win, if for different reasons, and each desires freedom: Zaroff from public persecution, and Rainsford from Zaroff. If Rainsford, at the end of the story, has become his enemy, then their only significant difference -- a defined moral compass -- has truly been erased.