Pearlpelt is a white gnawer first introduced in The Prophecy of Bane. He was destined to lead all of the gnawers and fight Gregor to the death. Most people refer to him as "the Bane". When Gregor finds him, he cannot bring himself to kill it because it is just a newborn.
Instead, he gives Pearlpelt to Ripred to take care of. The next year, Gregor meets The Bane again. Pearlpelt seems to be partially crazy. He tries to kill Ripred and than promptly busts into tears. A silver rat called Twirltongue persuades Pearlpelt to become king of the rats. Later, Gregor kills the Bane with the help of Ares.