Corr is a young otter.
Corr is shown as a kind otter who greatly admires Urchin and the other members of the tower from the stories that he'd heard when he lived with the otter colony. He also has a fiery spirit, as he didn't want to be cooped up in the colony for his whole life without adventure.
Corr is introduced as an otter who comes from the far side of the island of Mistmantle and has a massive family. He has a desire to meet Urchin and the other heroes from the tales that his family told him.
He meets Princess Catkin, who is living under the alias of Lapwing, as he makes his way to The Tower to see Brother Fir. When he first meets her, he finds Catkin rather bossy, but later they make fast friends and he shows her how to mend a boat with reeds and sap.
He bravely warns Padra of the attacking ravens when he goes looking for Kingsmantle seaweed to take it to Brother Fir. He stays in the Tower, contributing to the battle in many ways such as sinking the raven's boats and later, helping to rescue Princess Catkin from the Ravens with Fingal. He is later trained as a page by Urchin when a prophecy is made about him and Crispin discovers he is actually a Voyager, an animal who can leave Mistmantle and return more than twice.
When the Rage Tide sweeps Sepia away, he is given his first voyager quest of bringing her home.
He first lands on Whitewings and meets Queen Larch who treats him to food and rest from his journey, reporting that Sepia had not washed on her island, though she regretfully wished it were so. She gives Corr a jar of special honey from her garden that will keep his strength up. After leaving Whitewings, Corr lands on Swan Isle, which has been ravanged even worse than Mistmantle by the Rage Tide. He meets with Lord Crown, who is the new swan leader after the passing of his father, Lord Arcneck. Crown reports that he had seen a small boat with a struggling figure within it being swept past his island, which Corr guesses to be Sepia. Lord Crown decides to accompany Corr on his quest to find Sepia and sets out with the young otter to journey to Ashfire Island.
Corr and Lord Crown find Sepia on Ashfire Island, who is gravely ill from drinking the water (poisonous to all animals not native to Ashfire) on the island. As Corr rows Sepia home, Lord Crown tends to her by giving her portions of the honey given by Queen Larch to keep her alive. When Corr reaches the mists separating them from Mistmantle, he is forced to leave the boat and swim back to report to King Crispin and Queen Cedar. During the next few days, Corr and Crown take turns reporting to the island.
Corr retrieves the boat from within the mists that hold King Crispin's body and returns to to Mistmantle and his family. He later floats on his back in the water and watches the riding stars. After thet, Urchin is looking at him, and saying that he looked older out. The last we know is that he is going to join the Circle.