Simón is an invisible, ethereal demonic figure who repeatedly steals the Book. He is a red-haired man in his thirties, with violet eyes and a long beard, agitated and disoriented.
His invisibility is persistent: his blood becomes visible only once it loses contact with him, and the magic persists even after the conjurer’s death. Maristo defeats him with a spear or dagger. His death causes a spiritual depletion (merma) in Maristo.