Herman the Recluse
Herman the Recluse was, according to legend, a thirteenth century Benedictine monk best known as the supposed author of the Codex Gigas, or Devil's Bible.
The legend states that, as a resident of the Benedictine Monastery of Podlazice, Herman the Recluse was condemned to be walled up alive and starved to death. However, in a plea for his life, he convinced the Abbot to let him live if he could create a book that encapsulated all earthly knowledge in one night. Herman wrote until midnight, upon which he realized he could not finish his masterpiece and sold his soul to a Tebel-El in exchange for the ability to finish the Codex Gigas.