Choronzon (also known as 'Coronzon' or '333') is a demon or devil that originated in writing with the 16th century occultists Edward Kelley and John Dee within the latter's occult system of Enochian magic. In the 20th century he became an important element within the mystical system of Thelema, founded by Aleister Crowley, where he is the Dweller in the Abyss, believed to be the last great obstacle between the adept and enlightenment. Thelemites believe that if he is met with the proper preparation, then his function is to destroy the ego, which allows the adept to move beyond the Abyss of occult cosmology.
Crowley states that he and Victor Benjamin Neuburg evoked Choronzon in the Sahara Desert, December 1909. In Crowley's account, it is unclear whether Choronzon was invoked into an empty Solomonic triangle while Crowley sat elsewhere, or whether Crowley himself was the medium into which the demon was evoked. Nearly all writers except Lawrence Sutin take him to mean the latter. In the account, Choronzon is described as changing shape, which is read variously as an account of an actual metamorphosis, a subjective impression of Neuburg's, or fabrication on Crowley's part.
The account describes the demon throwing sand over the triangle in order to breach it, following which it attacked Neuburg 'in the form of a naked savage', forcing him to drive it back at the point of a dagger. Crowley's account has been criticised as unreliable, as the relevant original pages are torn from the notebook in which the account was written. This, along with other inconsistencies in the manuscript, has led to speculation that the event was heavily embroidered in order to support Crowley's own belief system. Crowley himself claimed, in a footnote to the account in Liber 418, that "(t)he greatest precautions were taken at the time, and have since been yet further fortified, to keep silence concerning the rite of evocation." Arthur Calder-Marshall, meanwhile, asserts in The Magic of my Youth that Neuburg gave a quite different account of the event, claiming that he and Crowley evoked the spirit of "a foreman builder from Ur of the Chaldees," who chose to call himself "P.472". The conversation begins when two British students ask Neuburg about a version of the story in which Crowley turned him into a zebra and sold him to a zoo. Neuburg's response in this book contradicts both the words attributed to him in Liber 418 and the statement of Crowley biographer Lawrence Sutin.
Choronzon is deemed to be held in check by the power of the Goddess Babalon, inhabitant of Binah, the third Sephirah of the Tree of Life. Both Choronzon and the Abyss are discussed in Crowley's Confessions (ch. 66):