Takahashi Rumiko Gekijou Ningyo no Mori EP2 - Village of the Fighting Fish (Part I)

In a flashback, Yuta recalls meeting Rin, the daughter of the pirate chief of Toba island. Rin's father was gravely ill, so Rin led raiding parties on passing ships, demanding a tenth of their cargo as a toll and sparing the crews. Rin buried Yuta after his body washed ashore following a violent storm. However, Yuta revived and explained that he drowned while mermaid hunting on behalf of Isago, the wife of the Sakagami Island chief who were rivals to Toba Islanders. Isago convinced the chief to use his men to hunt mermaids and Yuta was hired with some other men in a nearby port for the hunt. For a time, Yuta lived and worked with the Toba islanders. One day, Isago saw Yuta and Rin in port. Surprised to see Yuta alive, Isago realized that he was immortal and believed he had access to mermaid flesh. Isago followed them back to Toba and stabbed Rin's father in an attempt to force Yuta into revealing the location of mermaid flesh and stop him from dying. In angry retaliation, Rin slew Isago.