The Qlippoth (singular Qlippah) are rejected worlds that contain a half-made universe inhabited by creatures from before the creation of the modern Tapestry.
The essence of a Qlippah is not necessarily evil, but dangerous to mankind and the universe they have grown accustomed to. Some Qlippoth contain absolute aspects of God, which would render free will impossible and would allow no evolution of life, while others contain even more esoteric concepts that are too alien for the human mind to grasp.
Early infernalists called the Qlippoth the Nine Keys of Hell or the Nine Breaths of the Absolute, mocking the Egyptian concept of the Nine Cornerstones of Creation. The Order of Hermes, while borrowing lore from the Ahl-i-Batin, first defined the term in regard to the Spheres, with the Qlippoth representing its antithesis. Manipulating the essence of a Qlippah is the purview of those who have entered the Cauls and were remade.
Qlippoth is a kabbalistic term meaning "shells" or "husks"; they are the representation of evil or impure spiritual forces in Jewish mysticism, the polar opposites of the holy Sephiroth.