The Magnum Innominandum is an entity in the Cthulhu Mythos, whose name in Latin means "Great not-to-be Named". It is often associated with [[Hastur]. According to H.P. Lovecraft, this being is the spawn of Azathoth and progenitor of Yog-Sothoth, although the latter is dubious. One theory is that it is actually not Hastur's grandparent, but via Yog-Sothoth his parent. It is also known as the Nameless Mist. The reason for its title as "the unnameable" is an archaic use of the term, meaning not to be summoned or ritually named in an incantation. Cthulhu Cthulhu mythos is the label coined by the writer August Derleth for the shared world based upon the themes, characters, and story elements found in the works of H. P. Lovecraft, as well as his protegés and later writers influenced by him. ... Latin is the language originally spoken in the region around Rome called Latium. ... H. P. Lovecraft Howard Phillips Lovecraft (August 20, 1890–March 15, 1937) was an American author of fantasy and horror fiction, noted for giving horror stories a science fiction framework. ... Azathoth, a fictional godlike being, is referred to in the Weird Tales short stories of H. P. Lovecraft. ... The Key and the Gate. ...
According to H.P. Lovecraft, this being is the spawn of Azathoth (making it on par with the Magnum Tenebrosum and Cxaxukluth) and is associated with, and possibly the progenitor of, Yog-Sothoth.
Little is known about this god, but it is considered to be extremely dangerous to sorcerors, hence its title "the unnameable" (archaic terminology, meaning not to be summoned or ritually named in an incantation).
Xiurhn serves the Outer God known as the Magnum Tenebrosum and dwells in the Vale Which Is the Night in the Dreamlands.