Gathol existed as a planet.
Kenneth C. Flint, the author, gave permission to Joseph Bongiorno to release his previously unpublished Heart of the Jedi manuscript on the internet; however, Bongiorno made several modifications. Bongiorno stated that the planet Gathol was present in the original manuscript that was submitted to and reviewed by Lucasfilm before Bongiorno's fanon alterations, which involved renaming the planet.