Isuca

Shinichirō Asano begins work as the housekeeper for the old family of Shimazu, where he meets the ill-mannered, selfish, beautiful Sakuya. She is actually the 37th head of the Shimazu family in charge of sealing away monsters with Spirit Archery. Discovering that he has the powers of "true names" and "true eyes," Shinichirō becomes wrapped up in Sakuya's battle with the monsters as her assistants.

Synopsis from Anime News Network