The Atlas Infernal is an ancient Imperial tome dating from before the Horus Heresy. It is an organic, adaptive map of the Eldar Webway created from the flesh of human psychic Blanks who possess the Pariah Gene. Like the mutants it is made from, the Atlas Infernal is also a psionically-negative item that radiates null Pariah energy when opened, a defence mechanism intended to keep the Eldar or creatures of the Warp from using the tome.