Cyäegha is an obscure Great Old One and is characterized by its supreme nihilism and utter contempt for all things. The being appears as a great, black-bodied, green eye surrounded by a mass of tentacles. Cyäegha is served by toad-like monsters known as the Nagäae (possibly a derivative of "Nagae").
Cyäegha has existed since the dawn of time and sleeps in a vast cavern under the (probably fictitious) mountain Dunkelhügel, the "Dark Hill", in Germany. The inhabitants of the nearby farming village of Freihausgarten are descended from a cult that once worshipped Cyäegha. Cyäegha's worshippers draw upon the deity for vitality but also greatly fear awakening the god for its wrath is said to be terrible.
Cyäegha's cult became active in the town of Freihausgarten in the 17th century and remained so well into the 19th century. In 1860, the cult was disbanded by a young priest who died while battling it. Even so, once a month on the night of the full moon, the descendants of the former cultists are drawn to Dark Hill by a hypnotic, telepathic pull from Cyäegha. Once there, they are compelled to climb Dark Hill and perform a ritual that both appeases and binds Cyäegha. However, despite performing this ritual every month without fail, the villagers are not even aware that they practice the rite, and continue to fear the mountain and ordinarily avoid it.
The five Vaeyen
Cyäegha is both protected and imprisoned by five lesser demons known as the Vaeyen. They are "The Green Moon", "The White Fire Which Is Darker Than The Night", "The Winged Woman", "The White Dark Which Is More Red Than The Fire" and "The Black Light". The spirits of these guardians are contained in five vulturine statues which Cyäegha's worshippers use to keep their god in check.
Cyäegha is an earth elemental and is said to be a cousin to Nyogtha, another earth elemental. Cyäegha is also believed to be related to the Great Old One Othuyeg, because each appear alike and have similar habits. Like all the other Derlethian earth elementals, Cyäegha is adversely affected by the Ankh or Crux Ansata, the Vach-Viraj ritual, and the Tikkoun Elixir. References to Cyäegha are found in the Necronomicon, the Unaussprechlichen Kulten, the R'lyeh Text and its German translation Liyuhh, the Cthäat Aquadingen, and a few more obscure grimoires.
- Bertin, Eddy C. (1996) . "Darkness, My Name Is". In Edward P. Berglund (ed.). The Disciples of Cthulhu (1st ed. ed.). Oakland, CA: Chaosium. ISBN 1-56882-054-2.
- Harms, Daniel (1998). "Cyäegha". The Encyclopedia Cthulhiana (2nd ed. ed.). Oakland, CA: Chaosium. p. 71. ISBN 1-56882-119-0.