Hazel's brother, Fiver is small and nervous, but only because he sees far beyond what most rabbits see. Fiver knows that something bad will happen to the home warren, and Hazel trusts his brother enough to leave. Fiver guides the group through their travels, although he acts indirectly, through his brother. Hazel looks to Fiver for guidance, and when Fiver has a bad feeling about something the other rabbits rarely ignore him. In the warren of the snares, the only reason they do not heed Fiver until Bigwig is snared because they do not want to; they are too happy eating well and living easy to pay any attention to Fiver, and even Hazel does not want to listen. Nonetheless, Fiver saves the group. He is not enthralled by the easy life in the new warren because he does not care for it. Fiver wants to be free; he wants a home where the rabbits can live in peace and quiet and defend themselves from natural evils. Fiver seeks a normal rabbit life—nothing more, nothing less. Although he is a very unusual rabbit who uses very unusual means, he helps the group find their way.

There are times—such as when the rabbits have to cross the bridge—when the group is afraid, but Fiver trusts his instincts and his feeling that there is nothing to be afraid of. While the other rabbits are afraid of the unknown, especially man-made things, Fiver trusts his instincts. Although he is not at home among bridges and boats and cars, he knows that just because these things are unfamiliar does not mean that they are any worse than what the rabbits already know. In fact, he points out that the rabbits often face more danger from rabbits and familiar circumstances than from the unknown. Fiver is able to guide the others because he knows what he is looking for and he cannot be seduced by danger hidden amongst familiar surroundings.