According to demonologist Johan Weyer, Malphas was grand president of the infernal regions, where he appeared in the shape of a crow. When he appeared in human form, he had a very raucous voice. He built impregnable citadels and towers, overthrew the ramparts of his enemies, found good workmen, gave familiar spirits, received sacrifices, and deceived the sacrificers. Forty infernal legions were under his command.
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.