Agents of the Four Seasons: Dance of Autumn

A young girl lives on the northern tip of the Yamato archipelago in the land of Enishi. Her name is Kaya Fugeki, a descendant of the family that serves the Agents of the Four Seasons who has now found herself ascended to take on similar responsibilities as them. She is the one who brings day to Yamato-the Archer of Dawn. The young goddess mingles with the commonfolk as she attends school, yet nobody except for the handsome young man who serves her knows she is the country’s Day. Herein begins Kaya and Yuzuru’s story. (Source: Yen Press)

He is the one who brings about the darkness, the "Archer of Dusk." It is through his hard work that night falls peacefully every day. (Source: Dengeki Bunko, translated)