|Manga Debut||Chapter 16|
|Anime Debut||Episode 21|
|Voice Actor||Ikuko Tani|
|List of Characters|
Chizu Sakanaka (千津, Sakanaka Chizu) is the owner of the inn in Episode 21, where Natsume, Kitamoto and Nishimura were staying overnight. The inn was situated in a place surrounded with ponds, which the local place also famous with the mermaid legend.
When she was younger, she would always played at the nearby pond with Sasafune, without realizing that Sasafune is actually the legendary mermaid. They became good friends together.
At the same time, Chizu's neighbour, Keiichi, was sick and bedridden. Even so, he still tried to kept the young Chizu accompanied. However, when his health deteriorated fast, Chizu was sad and rushed to the nearby pond, remembering about the local legend. The legend says that anyone who drinks the blood of a mermaid, they can get immortality.
Desperate, the young Chizu called out to Sasafune, asking for her blood to cure Keiichi. Sasafune gave her a vial with red substance to Chizu. Chizu then fed him the blood and he was later transferred to a faraway hospital.
Present day, she waits at the local train station, thinking back about the past how she had made Keiichi's life miserable. She heard rumours that someone has seen Keiichi's appearance is not changing after all these years.
That's when she met Natsume and Sasafune. It is later revealed by Sasafune that the vial she gave Chizu back then was actually a grape juice. Chizu recalls the soft voice of Sasafune who had played with her before.