Kroova Wavedog was a rebellious, orphaned, and intelligent sea otter who befriended Sagaxus and Bescarum Whippscutt and brought them along on a voyage in his stolen vermin vessel, the Stopdog.
The voyage originally began with just the three of them enjoying their youth and discovering themselves, but after battling a shark and meeting the Migooch Tribe, they became embroiled with the Riftgard conflict between Triss, Shogg, and their pursuers, Plugg Firetail's freebooters and Princess Kurda. Kroova was a valued member of the party and was instrumental in the Redwallers defeat of the vermin. He and Shogg became good friends during the conflict, but sadly Shogg perished in battle with the adders Zassaliss, Harssacss, and Sesstra.
Kroova played a big part in freeing the slaves at Riftgard and defeating King Agarnu. He chose to stay instead of returning to Redwall with Triss. He eventually married a pretty ottermaid, Sleeve, whom he freed. He also became the adopted father of Freedom, an unclaimed mousebabe.