When Raziel proceeded to Avernus Cathedral in Defiance, he was able to forge and equip a new reaver - the Earth Reaver. This allowed Raziel to summon Earth platforms to reach the balcony level above; here Raziel found the Dark Scripture held by two statues. By taking the Dark Scripture to the main altar of the cathedral and placing it there, Raziel was able to open a portal that led to the Avernus Catacombs.
Visually the book seemed to be leather bound scripture with a rune symbol on the cover. The scripture was likely associated with the Cult of Hash'ak'gik.
- The Dark Scripture has much in common with the Bloodstained Book that Kain found in the Secret Altar to Hash'ak'gik in Avernus Cathedral in Blood Omen. Both are apparently involved with the Hash'ak'gik Cult, though notably the contents of the Dark Scripture are not revealed unlike its predecessor.
- A Lovecraft's Diary inscription on the floor of Avernus Cathedral reads "The book is the key to ultimate knowledge" - apparently in reference to the Dark scripture.