Stormfin was a giant male pike used by Mossflower otters to battle (and kill) the Gloomer. It was captured by Mask and Skipper Warthorn, and imprisoned in a stretch of the River Moss known as Camp Willow. Skipper kept it in a small channel by a sluice gate his otters had constructed, and unleashed it whenever they needed it to do battle. When the otters in the river heard the banging noise from a log they knew to get out of the water. Skipper said that it would always return because it knew there was food in its small channel.