An Illithid tadpole prepares to enter a human.

Ceremorphosis was a bodily change that occurred when an illithid tadpole reached maturity and was inserted into the brain of another humanoid being, usually a human. The tadpole ate away the victim's brain matter and essentially replaced the brain, erasing all of the subject's personality and memory, but leaving the physical body alive and under the tadpole's control. After this, "morphological transformations" occurred and after a week a new illithid was created.[1][2]

It was common for the newly formed illithid to retain a few memories of its former host. Those memories were merely vestigial and rarely affected the new individual's personality.[2]


If this was done with a non-human, the result was called a "half-illithid".[1] Another name for a half-illithid was "ceremorph".[3] They did, however, still possess most of the powers of a regular illithid.[1] Examples of creatures beyond humans that had undergone ceremorphosis successfully were:

An illithid tadpole that survived but was not submitted to ceremorphosis was called a neothelid.[3]



  1. 1.0 1.1 1.2 Eric Cagle, Jesse Decker, James Jacobs, Erik Mona, Matthew Sernett, Chris Thomasson, and James Wyatt (April 2003). Fiend Folio. (Wizards of the Coast), p. 90. ISBN 0-7869-2780-1.
  2. 2.0 2.1 Wizards RPG Team (2016). Volo's Guide to Monsters. (Wizards of the Coast), p. 72. ISBN 978-0786966011.
  3. 3.0 3.1 Eric L. Boyd (1999). Drizzt Do'Urden's Guide to the Underdark. (TSR, Inc), p. 22. ISBN 0-7869-1509-9.