An illuminated bible, and the largest existing medieval manuscript in the world. It is infamous for a unique and giant picture of the devil. The manuscript is believed to be from the early 12 century by the work of single monk over 5-12 years named Hermann the Recluse.
The legend of the codex was featured in the Black Tapes. The story tells of a monk, so despicable that his fellow monks had sentenced him to death by bricking him up in a wall. The monk begged for his freedom by promising to illustrate a bible that would cement the monastery’s fame. He promised to do this in one night. Either way, it was a ridiculous promise, but because he was such a talented illuminator, the monks took the bargain.
When the time came for the manuscript to be due, the monk was woefully behind, so he made a deal with Lucifer to help him finish the book in exchange for his soul. Hence, it forever became known as the Devil’s Bible.
A more reliable telling of the story can be found here.