"This black-bound tome seems to radiate a slight rotting smell, and the covers are unpleasant to the touch – like uncured human flesh left out in the sun. Rusted buckles on the cover seal it against the elements."

The Grimoire of Pestilential Thought is an item in Planescape: Torment. A codex of sorts, the book is full of long-forgotten knowledge meant to empower its user. Its use, however, comes at a cost.


Using the tome is evil. There are two ways the book can share its knowledge: it will grant spell scrolls after a series of sacrifices are completed, or it can be asked for general advice.

There are three sacrifices the book will ask of the Nameless One in return for power:

  • The first sacrifice involves the Nameless One spilling some of his own blood. Grants a scroll of Blindness.
  • The second sacrifice involves selling one of the Nameless One's companions into slavery. This can be done by speaking to Vrischika, in the Clerk's Ward. The book grants a scroll of Adder's Kiss.
  • The third sacrifice involves killing one of the Nameless One's companions, specifically without the use of magic. After, the book grants a scroll of Power Word, Kill.

The book can also be asked for advice. Asking for advice from it increases evil alignment at certain increments (third time asked, sixth time asked, ninth time asked, 12th time asked, and 15th time asked).


The grimoire can be looted or stolen from Mantuok, a wererat encountered in the Warrens of Thought.


  • Evil: following through on any of the book's requested sacrifices. The evil increase is granted upon reporting back in with the book after the second and third tasks.
  • Evil: asking the book for advice.
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