Charlie's Code Breaker
Saints represent groups of letters that represent numbers… that stand for concepts represented by… Oh, wow. I might be a genius.
Charlie's Code Breaker is a code decryptor devised by Charlie Bradbury before her death. It reveals how to decrypt both Nadya's Codex and through it, the Book of the Damned. The code decryptor reveals that the languages used in the book are Pre-Enochian, Sumerian, and other unknown various cuneiform-like symbols. The decryptor was sent to Sam's e-mail and used by Rowena to decrypt the Book of the Damned and find the cure for the Mark of Cain.
Charlie creates the code breaker after finding a pattern in the coding used in both the Book of the Damned and Nadya's Codex. However, Eldon Styne manages to find her and tries to break in. Charlie swiftly hides in the bathroom and sends the code breaker directly to Sam's e-mail before smashing her computer on the sink, which alerts Eldon of her location.
Sam receives Charlie's e-mail and opens the file attachment. He shows it to Rowena, who is surprised to discover that Charlie cracked the code before her death. With it, Rowena says that she can decipher every last word in the Book of the Damned and find the cure for the Mark of Cain.
The code breaker and Charlie's e-mail are seen on Sam's computer while he works on creating witch-killing bullets in the Bunker. Later, Rowena is able to find the page that contains the cure for the Mark of Cain in the book. Castiel sends the list of ingredients to Crowley who has no trouble retrieving them, including Oskar, someone Rowena loves. She is able to use the spell to destroy the Mark of Cain, but the blast breaks the iron shackles keeping Rowena restrained and her powers are bolstered by the book's influence. She casts an attack dog spell on Castiel to compel him to kill Crowley while she makes her escape with the Book of the Damned, Nadya's Codex, and her copy of Charlie's code breaker.
When Rowena is captured by the Winchesters, Sam and Dean find the codex and Rowena's copy of Charlie's code breaker in her suitcase. They agree to release her if she removes the attack dog spell from Castiel. Later, Sam acknowledges that without the codex or the code breaker, Rowena will have some trouble decrypting the book.
Rowena is captured by Crowley's demons and brought to the Needham Asylum, where Crowley and the Winchesters convince her to help in their fight against the Darkness. When Crowley agrees to call off his demon assassins in exchange for her help in summoning Lucifer in Hell, she asks for the codex and Charlie's code breaker. She is later seen with the book, the codex, and the code breaker in the Bunker's dungeon, searching for the summoning spell and sigils to nullify Lucifer's powers.