Maou Reijou no Shikousha - Isekai Shitsuji wa Ouse no Mama ni

Lute, a boy summoned to another world, is abandoned because he is considered inadequate. His fortunes change when Lurunoa, the only daughter of the Evil Presence Ruler, takes his hand and tells him he will become the head servant of her palace and live at her command. Lute finds himself serving three demon princesses, each with extraordinary hidden powers and mysteries. As the continent’s secrets come to light, the boy becomes a trump card for the world.