Scarlett Sinister is an evil witch attending Witch University and one of the daughters of Silas Sinister. She acts as the ringleader. She secretly defies the "No Magic" rule by using her powers whenever there is no teacher watching. She works with a few professors and her father to make Marnie open a box with the Cromwell family's ultimate magic inside. In the end, her plan backfires and she loses her family magic as a punishment for her father's actions.
Scarlett seems cold and harsh. She is conceited, and used to common attention. When her sisters lost their powers, Scarlett quoted, "Without our powers, we might as well be... UGLY!" She is very proud of her heritage. Boys seem to be in love with her, since they always do magical deeds for her and her sisters. Although most of their feelings is only for her looks, she invites the glances of those who also have "looks."
- All of her sisters, plus her father, begin with S.
- This could be a mimic of the 'P' tradition from Charmed, made by the writers of the movie.
- Many of her family's belongings have a snake in the shape of an S.
- Sapphire, Sage, and Scarlett rule the school.
- She is played by Kristy Wu.