Salamandastron

Salamandastron is a fantasy book, written by Brian Jacques in 1992. It is the fifth book in the Redwall series, and has been translated into four different languages.
Plot introduction.
Salamandastron, the mountain ruled by Badger Lord Urthstripe the Strong, and guarded by forty hares of the Long Patrol, is under siege by the weasel Ferahgo the Assassin, his son Klitch, and his vermin army of "Corpsemakers". Meanwhile, two stoats at Redwall Abbey accidentally kill a Brother of Redwall and then run away with the sword of Martin the Warrior. Mara (Urthstripe's adopted daughter) and Pikkle Ffolger, her trusted hare friend, are fooled by Klitch and his lackey, and Mara and Pikkle leave Salamandastron. Meanwhile, the deadly Dryditch Fever breaks out in Redwall...