this story is yet to be named. A Seto No Hanayome fanfiction

Seto Kumori
Straight, shoulder length black hair, bright blue eyes.
Kumori is Seto San's younger sister. She loves to read, and write poems and stories. She is very depressed and gloomy most of the time, because she is not adored, like San. Kumori is always happy when she is with Shark Fujishiro. In her mermaid form, her tail is light blue.

Seto San
Long, straight, dirty blond hair, brown eyes.
San is Kumori's older sister. She is very kind, and open-hearted. She often tries to reach out and comfort her sister, but it is usually a failed attempt. San is in love with Michishio Nagasumi. In San's mermaid form, her tail is dark pink.

Shark Fujishiro
Short, blond hair, yellow-green eyes.
Fujishirois very quiet at times, but not shy. Whenever there is a problem, according to Fujishiro, eating the person causing the chaos will solve it. Fuji is a shark, not a mermaid. He has the ability to change just his head into a shark head if he wants. He is most happy when he is with Kumori.

Michishio Nagasumi
Short, black hair, gray eyes.
Nagasumi is human, and he has to be married to San, becouse he knows of the existence of mermaids. Despite the fact that it is a forced marrige, San and Nagasumi are deeply in love.

Edomae Luna
Short pink hair,brown eyes.
Luna is of the Edome clan, not of the Seto clan. She classifies San as her rival, while San thinks of her as her best friend. Nagasumi is Luna's 'manservant' and she forces him to do what she wants. Luna is also a pop idol. In her mermaid form, Luna's tail is yellow.