Hayate is a cute, kind-hearted orphan in a wheelchair who is actually the mistress of the Book of Darkness and the Wolkenritter (Signum, Vita, Shamal and Zafira) but is unaware that they are causing harm to other people. Hayate's magic works slightly differently than that of Nanoha or Fate, in the fact that the closest thing she has to "familiars" are the Wolkenritter and her "weapon" is the Book of Darkness.