Sleeve was a young sea otter maid, a slave at Riftgard, and a friend of Triss and Drufo. Sleeve was born and raised in Riftgard Fortress, having no memory but that of hardship and cruelty under the rule of the Pure Ferrets. Her parents were also slaves at Riftgard, but they died when she was young. Sleeve was the author of the account detailing the overthrowing of the Pure Ferrets' regime; she entrusted her writings to Skipper of Otters, who took them back to Redwall with him.