Zenryaku, Onii-chan wa Seijo ni Narimashita

In this fantastical tale, a young man is forced to take on the role of a “Blessed Maiden” – a mystical figure tasked with casting spells using their own body – in place of his sister. He soon finds himself in a precarious situation when he catches the eye of an arrogant sorcerer, and a strange relationship begins to develop between the two.