IsaacHDXxx form2Isaac RebirthKeeper sprite

A gray book with an inverted pentagram on its cover.


Upon activation, blood will run from Isaac's (now empty) eye sockets, and will also have a red Cross of St. Peter on his forehead. This adds 2 points of Damage for the current room.

In addition to its +2 base damage modifier, if Isaac holds Blood Of The Martyr (without also having Max's Head or Magic Mushroom), the book gives a 1.5x damage multiplier.

Increases the chance of a Devil Room spawning by 25%.


  • Judas starts the game with this item.




  • In the Dead Sea Scrolls, (not to be confused with the item of the same name) Belial is the leader of the Sons of Darkness.
  • During development, there was an item known as Satanic Bible. It later evolved into the Book Of Belial.
    • The Book of Belial is the third book of The Satanic Bible, and describes magic rituals.
  • XV The Devil shares its effect with this item and does not stack with the Book of Belial.
  • The upside down pentagram on the book is a widely known satanic ritual symbol.
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