Shoukan wo Suberu Yami no Kizoku ni Tensei Shita: Bishoujo Tachi to NIjuu Seikatsu no Harem LifeShoukan o Suberu Yami no Kizoku ni Tensei Shita: Bishoujo-tachi to Nijuu Seikatsu no Harem Life; Reincarnated as a Dark Aristocrat Who Rules a Brothel: A Harem Life of Double Life with Beautiful Girls; 娼館を統べる闇の貴族に転生した　～美少女たちと二重生活のハーレムライフ～

I was overworked and unlucky enough to be hit by a train and died... However, before I knew it, I had been reincarnated in another world as a baby of the aristocratic Valsh family...! The level of civilization was about the same as that of modern times, and it seemed that they could live without any inconvenience. In fact, the valsh family has a secret family business, and at the age of fourteen, I became the boss of the mafia that rules the brothel... !?