A surface-dweller who kicks off the story by accidentally fishing up Manaka, becoming her first friend in the human world. He comes from a fishing family and has a genuine love for both the sea and its people.
Tsumugu's the quiet type—calm, collected, and pretty much keeping to himself. He rarely smiles and doesn't show much emotion, which makes him come across as either stoic or just straightforwardly matter-of-fact. He's genuinely curious about things that interest him, but he doesn't have much drive to pursue them; he'd rather watch and think before doing anything. That said, his emotionless exterior is misleading. He's confessed to Miuna that he actually has feelings—he just has no idea how to express them.
Content compiled by AnimeList.moe from publicly available sources.
