Grey-litten Y'qaa, a.k.a. the abyss of Y'qaa, or the Cavern of Y'quaa is an underground realm inhabited by the primordial being Ubbo-Sathla, and the current location of the Elder Records. The location first appeared unnamed in Clark Ashton Smith's story "Ubbo-Sathla", while the name was coined by Lin Carter for his Xothic Legend Cycle.
In Carter's "The Descent into the Abyss", the realm of Y'qaa can be reached by the tunnels deep inside Mount Voormithadreth in Hyperborea, which suggests that it might be intended to be the abode of Abhoth, the "Source of Uncleanliness", as featured in Smith's "The Seven Geases". This could be an allusion to the similarity between Ubbo-Sathla and Abhoth, proposed by Gary Myers to be two different names for the same deity.
The alternate spelling Y'quaa is used in the 2020 edition of the Malleus Monstrorum, in which the cavern is associated with both Abhoth and Ubbo-Sathla.
Description[]
A grey-litten abyss identified as multidimensional, "coterminous with many worlds and planes of existence", including Yarnak. Nevertheless, Y'qaa can be accessed by the interior of Mt. Voormithadreth, past the cavern of the Prototypes. Its entrance is guarded by K'thugguol, the Grand Shoggoth. Ubbo-Sathla dwells there with the Elder Records it stole from the Elder Gods. The legendary power of these tablets has tempted many sorcerers to brave the abyss and try to retrieve them, but none has been successful so far. (EXP: "The Descent into the Abyss")