If it was satisfied with the user, it conferred additional abilities like one usable for ranged attack or increased usefulness as an implement, granting additional knowledge, and the ability to induce fear into others. It could also make its intentions discernible for the reader by moving words on its pages around.
It could deliberately hide its more dangerous content to make it appear less dangerous or malicious.
Creatures called with summoning abilities became deadlier if the book was used but this also came at the cost of accelerated corruption. This corrupting effect could be deliberately hastened if the user wanted to hinder his or her enemies from escaping their own effects or use the book's powers to make an otherwise botched attack into a successful one. The book actually modified their personality to become that of a chaotic evil person. The book had an actual corrupting effect on the personality of the user and those within 5 feet (1.5 meters) from the user. The book could be used as a magical implement that was more effective against non-evil creatures than against evil ones. For example, the user learned the Dark Speech. He or she became generally more knowledgeable on evil matters. The owner of this book was given additional knowledge about arcane, historical, and religious matters. Ī lich reading from the Book of Vile Darkness. The book was so evil that it prevented plant life from growing. If a good divine spellcaster tried to read the book, the person died or at the least went permanently insane, like under an insanity spell, and the book drained his or her essence without conferring any benefits. Looking into it brought them the hostile attention of a fiend, who attacked them on the night they looked into the book, though this happened only four in five times. To good people, even touching the book was dangerous. If they also happened to be a divine spellcaster, the book sapped their essence away but conferred no benefits. Reading it physically harmed them and their personality changing it to that of an evil person. To neutral people, the book was dangerous. In fact, the reader could use a dominate monster effect on a evil person. It also disfigured the user so that he or she became more intimidating to non-evil people, while becoming more respected by evil people. Reading the book strengthened one aspect of the user at the cost of another aspect. Upon completion, an evil divine spellcaster, such as a cleric, gained enough insight that it allowed him or her to grow in power and become more insightful into matters in general. Reading the entire Book of Vile Darkness took about seven days or, to be more precise, eighty hours. Therefore, it took a long time to read through the book. A major reason why these books were so hard to read and navigate through was its non-uniformity.
Therefore, the books looked ugly, they had pages made from different materials, and they had different writing styles. The book could be edited by the owner and the owners of a book did so without regard to uniformity of the material or the look of the book. It had-at least for normal people-unintelligible symbols on the cover. The latter was made into the book's metal binding via magic. The original from Vecna, a deity from Oerth, was a book with a cover made from flesh from a human face and bones from a demon. There were a total of six copies and at least eighteen fakes and botched copies of it.