Sun Seto is the main female character as well as the show's mermaid from the anime series, "My Bride Is A Mermaid".
She is the lover of Nagasumi Michishio. Her father run a group called the Seto Group. She has light brown hair and has pinkish red tail (which also matches her school uniform). She has a childhood friend and rival in Lunar Edomae.
She is voiced by Alexis Tipton in the English dub.