Isabeau, also known as Isabeau de Bavière (Isabeau of Bavaria), is the main antagonist in Puella Magi Tart Magica: The Legend of "Jeanne d'Arc". She is the Queen of France.
- Eye colour: Yellow
- Hair colour: Blonde
- Soul gem:
- Witch form: Crépuscule de La Reine
- Wish: For everything you (Kyubey) possess.
- Japanese pronoun:
- Known relatives:
Because of her wish, Isabeau gained the same abilities and knowledge as Kyubey, making her partly an Incubator, magical girl, and ultimately, a witch. She could create magical girls and grant their wishes, and her body also couldn't be permanently destroyed. Due to the wishes of Minou and Lapin, she came a witch in a human shell and couldn't be defeated by any ordinary magical girls with the exception of Tart.
- Out of all the witches that appear in Tart Magica, Isabeau's witch is the only one that is named.
- Her witch name is French and translates to, "Twilight of the Queen".