Katou Umi

She is the protagonist's second cousin.
She has been living in the big city of Tokyo, so she has been longing to live in the country side.
She came alone to the island this summer.

Throughout the summer, she will also be be taking care of the protagonist's meal. She has extraordinary passion for fried rice and she excels at cooking it.

Spoiler

Her real name is Takahara Umi (鷹原 羽未), the daughter of Hairi and Shiroha in the future.