Islinn is the leader of the Seal Clan and first appears in Spirit Walker. He is described as appearing very old, with white hair that has slate beads woven into it and rheumy eyes. He has seashell piercings that weigh down his earlobes. He has a wheezy, breathless voice and seems to be in declining health due to his age. He seems to bend often to the will of Tenris, who appears to advise him and make decisions for him.

He once had a son who was killed by the same sickness that drives the plot of Spirit Walker but this is only mentioned briefly.