Folgrim was a male otter. He was the son of Bargud, brother of Tungro, grandson of Daddo, and the nephew of Garraway Bullow, Warthorn, and Riverwyte. Folgrim was said to resemble Riverwyte in his warrior ways.
Folgrim was originally a member of Tungro's Holt. He was described as a stoic, silent creature who rarely smiled and a fiercer warrior than Tungro despite being younger. After they drove off a vermin attack on their holt, Folgrim gave chase alone and was captured by vermin. They tortured him for two seasons. When he returned, he had only one eye, crippled paws, many deep scars all over his body, and mental trauma.
Folgrim experienced great difficulty in readjusting to normal life in the otter society and was banished several times for cannibalism and violent, inappropriate behavior. Each time Folgrim left, however, his brother forgave him and sought him out.
Folgrim was encountered by Martin the Warrior and his companions during a particularly heavy rain storm, where he was witnessed killing one of two rats attacking him. When Folgrim met Chugger, a mischievous and amusing baby squirrel, the unwell otter suddenly and unexpectedly laughed. Noting the change in his brother, Tungro agreed to let Martin and his companions bring Folgrim on their quest. During the course of their adventures, thanks to Chugger's friendship and the care of Trimp the Rover, Folgrim became stable and regained a taste for vegetarian food. Folgrim proved to be a very reliable and loyal companion and was recognized as a warrior by all who met him.
Folgrim was eventually welcomed back into the holt when he returned from his journey. He settled down with his uncle, Skipper Warthorn, in Redwall Abbey.
Not to be confused with Forgrin.