According to the demonologist Johan Weyer, Bitru is a great Prince of Hell, also known as Sytry. He appeared in the form of a leopard with the wings of a griffin. But whenever he adopted a human appearance, it was invariably one of great beauty. It is he who awakes lust in the human heart. Seventy legions obey his commands.
Weyer, Johannes. Witches, Devils, and Doctors in the Renaissance: Johann Weyer, De Praestigiis. Edited by George Mora. Binghamton, N.Y.: Medieval and Renaissance Texts and Studies, 1991.