Bernkastel's double and servant. Also a piece who has manifested in the human world.

Because she is human, she cannot use magic and the like. However, she can appeal to Bernkastel on a higher-level plane to obtain miracles and various authorities she can use, so it would probably be no exaggeration to call her a human capable of wielding the power of a witch.

Through Bernkastel, she has been given the detective's authority while on the game board.

Therefore, even though she is an outsider to the Ushiromiya family, she possesses the right to demand full attention from everyone when speaking, the right to advance proceedings, the right to investigate the crime scene before the police arrive, and many other special abilities.

She gets pleasure from the process of solving riddles, but her greatest joy comes from using that victory to sneer at others.