Hana to Enbukyoku

An unusually pale demon becomes the maid of a beautifully dark-skinned duchess with great magic ability in hopes that being physically close to powerful magic will darken her skin.

A girl is taken away, declared the so-called "Great Mermaid" who must return to her true origin, the sea. In her time spent in isolation, she meets a new friend - or is it a foe?

A young girl, Fumi, was sent from Tokyo to live with her aunt in the countryside. She was confused by her new environment, and was often bullied to tears by the local children while she was little. Five years have passed, and Fumi had become a pretty schoolgirl in her sailor suit uniform. Although she didn't actively chat and mingle with her classmates, she did have a special friend with whom she spent time after school. The nostalgic wooden school building and the light-hearted conversations of everyday life draw the reader into the faint sentimentality of a bygone era. A love story between two people that do not overlap. (Source: Aokishi, translated)

One-shot by Sagan Akagawa published in Aokishi 3B.