Sakuya is the only human living in the Scarlet Devil Mansion, yet she is also the head maid. Hieda no Akyuu theorizes that she had been a vampire hunter before she began working in the mansion, but was defeated by Remilia Scarlet who pitied her and gave Sakuya her current name.

Though she looks about sixteen like the other girls, Sakuya has the ability to Manipulate Time, which comes with being able to stop, slowing and speding it up altogether. She seems to have been serving Remilia for a long time and may be far older then she looks. Socially, she interacts mainly with the others in the Scarlet Devil Mansion.

Her talents are cooking, knife throwing and time manipulation. The latter two abilities characterize her appearances in-game, and led to frequent parodies in reference to Dio Brando of JoJo's Bizarre Adventure, who also controls time and throws knives. This reference goes so far as Sakuya using some of his poses in a game. She is often associated with dogs by other characters because she is serving as a demon's "faithful guard dog" even though she is a full blood human. Due to the inconsistent artwork depicting her bust between games, dōjinshi often make fun of her by indicating that she pads her breasts.

(Source: Wikipedia)