Sakuya Izayoi (十六夜　咲夜 Izayoi Sakuya) is the Chief Maid who serves Remilia Scarlet, the head of the Scarlet Devil Mansion. She is the only human living in the Scarlet Devil Mansion.

Sakuya is seen with blue eyes, silver hair worn in long braids on both sides of her face with green bows at the ends and a white maid headband. She wears white and dark blue French maid's outfit with an apron, short sleeves and a green ribbon. She also carries her knives and, additionally, wears stockings.

Abilities: Manipulating Space-Time. Sakuya possesses the ability to manipulate time, where she's able to control the flow of time, such as speeding up time, slowing it down, erasing it, and stopping time altogether. She is also able to manipulate space, and can narrow or lengthen it: she made the Scarlet Devil Mansion, which was originally spacious, even more abundantly spacious, and furthermore just like this she cleans alone. By manipulating space-time, Sakuya is also capable of creating another Sakuya and making it appear in front of her, which will execute a different action to that of the original. This is apparently related to "another time" though it isn't explained thoroughly.