Romsca was a female ferret corsair and the captain of the Waveworm. She originally served as Conva's first mate and took on the role of captain after his death. At the request of Ublaz Mad Eyes, she and her crew escorted Lask Frildur and a score of his monitor lizards across the western sea to Mossflower Woods in search of the Tears of all Oceans. Since the Pearls were within the walls of Redwall Abbey and had not yet been discovered, Lask captured Abbot Durral for ransom, and Romsca sailed the Waveworm back towards Sampetra with the captive.
However, Lask and Romsca despised one another, and the rivalry grew to a peak on the return voyage. Lask and his lizards were needlessly cruel to old Durral, and Romsca befriended the mouse Abbot and protected him. She fought Lask to the death, and her crew and the monitor lizards completely killed each other off. Romsca herself slew Lask, but her own injuries were severe; she died from a horrific wound across her spine.
Durral, the last living and unharmed creature onboard the vessel, tended to Romsca as she was dying and listened to her confessions and wishes to have been a goodbeast. Romsca also gave Durral instructions on how to sail the ship the rest of the way to Sampetra, as it was too late to turn around, and told him to seek help from her friends on the island. Right before Romsca died, Abbot Durral called her child, and she replied, "My child. I like that. Thank ye, father." This seemed to confirm a significant change in her perspective on life.