The being first appeared in the short story "The Lair of the Star-Spawn" (1932) by August Derleth and Mark Schorer.
The being came from the star Arcturus, but now dwells beneath the buried city of Alaozar on the Plateau of Sung.
Zhar is believed to be physically connected to its "twin", Lloigor, perhaps by a long extension of tentacles.
Lloigor appears as a titanic, winged mound of undulating tentacles and is also served by a cult known as the Tcho-Tcho's Brotherhood of the Star Treader.
Though the actual site has never been discovered, it is nonetheless venerated as a holy place by the Tcho-Tcho people because it is home to Zhar and Lloigor.