Nataraj represents the "good" in the story, and Vasu is the "evil". On a large scale, each character represents the two cultures of India and Britain, and the effects of British colonialism on the Indian people. Vasu is the commercialism of Western society, and Nataraj is the traditional, peaceful way of life.
In the story, Vasu is characterized as a demon by Sastri, Nataraj's assistant, and Sastri's comparison foreshadows Vasu's destruction just as the demon was destroyed. Vasu is physically strong and bullies everyone in the town. He's brutal, self-centered, and has no respect for tradition, religion, or morality. He easily intimidates others by his large size and his aggressive behavior. As a taxidermist, he poaches the animals in the jungle, stuffing them for money. To practice his taxidermy, Vasu steals pets and stuffs them before attempting to stuff the larger, more expensive animals. When others complain, Nataraj asks him to leave, but Vasu ignores this request.
Nataraj begins the story as a passive, caring family man who enjoys his life and being the boss of his printing business. He was brought up to believe that killing a fly is a sin, and when Nataraj sees the animals Vasu has killed, he's stunned. He doesn't know how to deal with someone like Vasu.
The author emphasizes the theme of good vs. evil when Sastri says, "Evil has in it, buried subtly, the infallible seeds of its own destruction."