The wife of the Sakagami Island headman. Isago told her husband of the immortality of the mermaid's flesh and encouraged him to find one. Isago is pregnant from her former husband who was murdered by the Sakagami pirates three years earlier. In order to give birth to a healthy child, Isago needs to eat the mermaid flesh, because she is in fact a mermaid. She tells Rin that there are mermaids who can walk on land and mermaids who swim at sea. The ones who walk on land eat the swimming mermaids' flesh, especially during pregnancy. Isago finally ate mermaid flesh, dived into the ocean, transformed back into a mermaid, and gave birth to two healthy babies