メア＝S＝エフェメラル

Likes: Hibarigasaki's starry sky
Dislikes: First-time partner

A mysterious girl who appeared in the lookout where You made a promise with a girl in his past. She calls herself a shinigami who can reap only peoples' nightmares. "Mare S. Ephemeral" is her Shinigami name, and her real name is unknown. She gets annoyed easily and tends to forget names quickly, but is also quite shy when she meets new people.

Mare is actually the same as Ren: she is a spirit of her respective meteorite. Mare is the meteorite that fell down on the day You left to the city and Yume was admitted to the hospital, and thought it to be a shooting star, so they both wished upon it. Her whereabouts are unknown, and this proves to be a difficult task for You and Yume who are supposed to find it after Mare sacrifices herself.

Her reincarnated name is Kogasaka Mea / 小河坂 芽愛