grimoire of alice

The demonic tome Alice Margatroid used as a weapon in the Extra Stage of Touhou Mystic Square and continues to keep on her person in later appearances. Using the book appears to unlock Alice's full potential, but due to her cowardly inner nature and her fear of the implications if she lost a fight at full power, Alice normally keeps the tome wrapped in two padlocked leather bands, primarily relying on her dolls like Shanghai and Hourai in combat. Using the tome allowed Alice to fight on the level of an Extra Stage Boss, compared to her later showing as the Stage Three boss of Perfect Cherry Blossom

A common theory attempting to link the PC98 and Windows eras of canon is that use of the Grimoire is what changed Alice from a human into a Magician Youkai.