"Rikki-Tikki-Tavi" comes down pretty hard on the whole good versus evil thing. In this corner, wearing his fur raised, we have the valiant, the fearless, the good Rikki-tikki. He fights to protect the innocent people of the bungalow, especially their boy, Teddy. In the other corner, wearing scales black as onyx, are the evil, vicious, and downright nasty cobras, Nag and Nagaina. They want to kill the humans so they can become the undisputed rules of the garden. Between these corners is a middle ground where no character can survive. Seriously, you're either with the good guys or you're the evil ones here. Get off the fence and pick a side.
The characters aligned with good in the story are action-oriented.
The only evil characters in the story are cold-blooded snakes. The good characters are all warm-blooded animals.