Fiver_ the Lagcaous

Fiver: Hazel's younger brother. His Lapine name is Hrairoo, meaning "Little Thousand" (in the Lapine language any number larger than four is "hrair" or "a thousand"; Fiver was the last and smallest of a litter of five or more rabbits). A seer, his visions guide his considerable wisdom, such as when he realizes the true danger of the snared warren, which wins him the respect of his fellows, who eventually come to accept his counsel without question. For example, when Hazel was dying because of a gunshot in a raid on a human farm's rabbit hutch, Fiver has a vision that enables him to save his brother. It is implied, later in the book, that he also gives Hazel a vision that inspires him to set up the release of the Nuthanger Farm guard dog to save the Watership Down warren from General Woundwort.
In the TV series, Fiver's visions come in rhymes, and he often feels responsible for the terrible things, blaming himself for their outcome. In the 2018 miniseries, he takes Hazel's place during the story's climax in being captured by the cat Tab and rescued by the farmer's daughter.