Books of Zeref

The Books of Zeref are, as the name suggests, a series of Magic books written by the Black Mage Zeref, containing various spells of the Black Arts.

Appearance
Not much is known about the appearance of each book, but the book containing E.N.D. is shown as a slightly tatty volume with various rips and tears in the cover. It has Zeref's name written in large black letters on the cover and the spine. On the front cover, there is a picture of a glowing eye in darkness with several wavy lines spiraling inwards towards it.

Contents
The books contain knowledge on the Black Arts which Zeref used. Many of the spells known to come from the books involve the creation of demons. Each demon is summoned by their own book. Walrod Cken speculates that one specific book, the book of the most powerful of Zeref's demons E.N.D., may be in the possession of Tartarus, a Dark Guild whose members consist of Demons originating from the books.
 * Lullaby: This demon, usually in the form of a flute that kills anyone who hears its tune besides the player, is said by Goldmine to be from the book.
 * Deliora: According to Erza Scarlet, this Demon is also likely one from the Book of Zeref.
 * Nemesis: This spell comes from Chapter 4, Section 12 of the book, and allows the user to create Demons from rocks.
 * Eclipse: The Eclipse Gate uses a combination of Magic from the book and Celestial Spirit Magic to enable time travel.
 * Doriate: When Doriate assumes a demonic form, Gray Fullbuster, who witnessed Deliora, comes to the conclusion that he is a Demon from the book.
 * According to Cobra, Tartarus is made up entirely of Demons originating from the book.
 * E.N.D.: Tartarus' Guild Master, described by Atlas Flame as the vilest Demon from the Book of Zeref. According to him, Igneel tried and failed to stop it 400 years ago.