The Horrendus Libri is said to have been written around 219 AD by the Mad Episcopal Lucas Of Antioch. While the other prophets of his time were arguing what was the true faith that would enlighten mankind in the Third century, Lucas was searching for more ancient truths. A prophet of the Arian faith, he wasn't happy, nor satisfied with the growing influence of the Nicene Christian or Catholic faiths of the world around him. Being fluent in Latin, the monk transcribed his native proto-Slavic language into a cypher where he could write down the mysteries that he solved. Delving past cryptic tenets of Judaism and eldritch pagan scripture, he unlocked horrible secrets. These secrets, more often than not, are best left forgotten, if not just left well enough unknown. Lucas is said to have lived until 999AD before a company of crusading knights stored his small castle, known as the Black Tower, and decapitated him. Later they burned his corpse to ensure that he could not somehow return. His written works lived on in the darker realms of occult study and the halls of under-funded academia.
It is also said that the man was able to cast sorcery or more specifically "grave-spawned magics of horrifying consequences" (according to Phillipus of Nicodemus IX) upon those that encountered him. Supposedly he lived on an island where the bodies of the dead buried there served him and acted as his body guards. It is believed that he is also the founder of many Satanic cults across all of the known world. During the legendary nearly eight hundred years of his life, it is said six copies of the unholy manuscript were completed. With the advent of the printing press, some twenty-two more issues of the dark work, entitled D' Libre Horribles, were reportedly cranked out-- a lot is said to have been edited out in these later works.
This book, Le Libri Horrendus is at a glance a book full of gruesome and grotesque drawings, written in a secret code, with geometrical patterns that do not make sense. But for those that somehow get it, amazing supernatural abilities are just around the corner. In game terms, the Character can learn magical spells from reading it with a Mental Draw at 1, but suffer a -1 modifier on every Charm check per reading for that session.