Krauss and Natsuhi's eighteen-year-old daughter. She is an energetic young girl, serving as the student body president at her school, and even leading a rock band. If her father inherits the family fortune, she will become the heiress to the Ushiromiya family, although the family's patriarchal hierarchy denotes her future husband will become the next head. Jessica is tomboyish, feisty, and rebellious, much to the dismay of her mother, who insists she act more refined and ladylike. She dislikes her parents at times for the pressures they place on her regarding the family inheritance, which she has no interest in. However, she still shows concern for them deep down. She was born with weak bronchi, and occasionally suffers from asthma attacks.
She is in love with Kanon, who tries to hide his own feelings from her, though she manages to reach out to him in Dawn of the Golden Witch, and they become a couple. She is willing to go to great lengths to gain Kanon's respect, and tries to avoid doing anything that could jeopardize that. Jessica is shown to be skilled with brass knuckles in Alliance of the Golden Witch.