The Taggerung

Book summary - Sawney Rath, the leader of a vermin clan, believes Deyna, an otter born
of the community at Redwall, is their Taggerung, a warrior destined to
lead them to power and greatness. Little does Rath realize that when
Deyna grows up, he will become the bane of vermin across all Mossflower
Woods.

Of all of the Redwall books I've read so far this one and the first one, Redwall, are my favorites.  Truly enjoyable read.