The Perann Nebula, a nebula situated far into the Unknown Regions, possessed a striking scarlet luminescence. This glow was a result of the energy emitted by the twelve stellar clusters connected to it, which were together called the Nihil Retreat. The planet Rhand, home to the Sorcerers of Rhand, was found nestled within this nebula.
While Luke Skywalker and the Shadows of Mindor initially described the Nihil Retreat as "twelve stellar clusters within" the Perann Nebula, The Unknown Regions later presented it as "a protective bulwark around the Perann Nebula." The Star Wars: The Essential Atlas Online Companion in its 2015 revision, succinctly positioned the Perann Nebula within the Unknown Regions. To date, Lucasfilm has not offered any explanation to resolve these differing accounts.