Rikki_Tikki is a mongoose. The story is about his battle against the cobras
Darzee and his wife
Nag and Nagaina are Indian cobras. Nag and Nagaina are the villains in this story trying to kill the British family.
The bird is the "town-crier " of the garden. The Coppersmith sings the news that Nag and Nagaina are dead.
Darzee and his wife are both tailorbirds. Darzee is a songbird which means he has a beautiful voice, but that's about it. His wife is the exact opposite of him, she is practical and levelheaded and knows she must help Rikki-Tikki distract Nagaina so he can destroy the nest.
Chuchundra is a muskrat that dosen't have much characterization except being a foil for Rikki-Tikki.