Ane Naru Mono
Other names: 姉なるもの, 恶魔姐姐, The Demon Who Became My Sister, The Sister of the Woods with a Thousand Young
Author: Iida Pochi.
Artis: Iida Pochi.
From Kirei Cake: Adapted from the doujinshi series of the same name, The Demon Who Became My Sister is a heart-warming story of how a neglected orphan, Yuu, has been blessed with the offering of a free wish by a demon, and he simply asks her to become his older sister.