Characterization is how an author presents a character's personality. The two methods for doing so are direct characterization and indirect characterization. Direct characterization has the author divulging to the reader a character's personality traits outright ("Jane was a greedy kid"), while indirect characterization generally reveals personality through the character's words or actions (we see Jane hoarding cookies during snack time at the expense of the other kids).
In "The Most Dangerous Game," characterization is indirect. The characters' personalities are not described outright, but they do share their philosophies and motives through dialogue. For example, Rainsford's first exchange with Whitney reveals a great deal about him:
"It will be light enough in Rio," promised Whitney. "We should make it in a few days. I hope the jaguar guns have come from Purdey's. We should have some good hunting up the Amazon. Great sport, hunting."
"The best sport in the world," agreed Rainsford.
"For the hunter," amended Whitney. "Not for the jaguar."
"Don't talk rot, Whitney," said Rainsford. "You're a big-game hunter, not a philosopher. Who cares how a
"Perhaps the jaguar does," observed Whitney.
"Bah! They've no understanding."
"Even so, I rather think they understand one thing—fear. The fear of pain and the fear of death."
"Nonsense," laughed Rainsford. "This hot weather is making you soft, Whitney. Be a realist. The world is made up of two classes—the hunters and the huntees. Luckily, you and I are hunters. Do you think we've
passed that island yet?"
Within these few lines, the reader learns Rainsford is a passionate hunter characterized by arrogance and lack of compassion for the animals he hunts. It can also be inferred that he has never known true fear or what it is to be hunted. He never says any of that directly, but the reader is able to glean it from the conversation.
The physical description of Zaroff is also indirect: Rainsford gets the impression of an aristocrat, signifying culture and intelligence, but then he sees that Zaroff has "red lips and pointed teeth," creating a savage contrast with his "handsome" appearance. The narrator never says "Zaroff looked like a predator with his sharp teeth and red lips," because the reader can already make that connection on their own.
These details are meant to make the reader uneasy before it is revealed that Zaroff hunts humans for sport, which is one of the subtle strengths of indirect characterization. Had O'Connell outright said, "Zaroff looked like a monster and he had no respect for human life," the suspense and pacing would have been sacrificed.