Ai Hayasaka is a second-year student at Shuchiin Academy and a valet of the Shinomiya family. She is a member of the Hayasaka family, who have served the Shinomiya family for generations, gaining their trust. Having been personally assigned to enter Shuchiin Academy with her, Ai supports Kaguya Shinomiya in her high school life and has been a part of Kaguya's life for ten years. Because of their close relationship, Ai is one of the few people around to which Kaguya's amiability is not an act. Even if she demonstrates maturity as a valet, Ai still has the concerns of a young girl, such as caring to be in fashion and going out with friends, even if she does not have much time for herself due to work. Ai helps Kaguya with the struggles about her feelings for Shirogane.

Spoiler

She later leaves her job as a maid to Kaguya but still continues her friendship.

Spoiler

In the Doujin-ban universe, she starts dating and later gets engaged to Shirogane