Physically, Zaroff is tall, handsome, middle-aged, and slender. However, it is the other aspects of Zaroff that are interesting. I am quoting from the story off the internet, so the page numbers I am using are from that copy. The adjectives are bolded.
First of all, Zaroff is rich. His father had been rich in Russia, but Zaroff had to leave that country and lost everything. However,
“I, luckily had invested heavily in American securities, so I never have to open a tearoom in Monte Carlo or drive a taxi in Paris.” (pg 4)
He also lives in a mansion on an island. Rainsford observed
“It suggested a baronial hall of feudal times with its oaken panels, its high ceiling, its vast refectory tables where twoscore (40 people) men could sit down and eat. “ (pg 3)
Zaroff is also cultured and cosmopolitan, which means that he could represent many different parts of the world. He is an expert on wines, foods, and the finer things in life. When Rainsford is escorted to his room, he finds an evening suit laid out for him and “noticed that it came from a London tailor who ordinarily cut and sewed for none below the rank of duke.” (pg 3)
Rainsford wonders how Zaroff recognizes his name. Zaroff shows that he is well-read and multi-lingual when he explains to Rainsford ,
“I read all books on hunting published in English, French, and Russian.” (pg 4)
The fact that he is bored, has stimulated his interest in hunting men. He no longer finds hunting animals exhilarating.
“Hunting has ceased to be what you call ‘a sporting proposition’. It had become too easy. I always got my quarry. Alwys. There is no greater bore than perfection.” (pg 4)
This boredom led him to start hunting mankind, and makes Zaroff immoral. He does not care for the lives of the people he hunts. He criticizes Rainsford for harboring,
“…. romantic ideas about the value of a human life.” (pg 5)
Finally, because Zaroff has spent so many years hunting, he has become very observant and analytical. He explains to Rainsford,
“….mine is an analytical mind, Mr. Rainsford. Doubtless that is why I enjoy the problems of the chase.” (pg 4)
When they are in the hunt, Rainsford notices that,
“Nothing escaped those searching black eyes, no crushed blade of grass, no bent twig, no mark, no matter how faint, in the moss.” (pg 8)