Demogorgon /(dē"mō̇*gôr*gŏn [or] dĕm"ō̇-)/

De·mo·gor·gon

Demogorgon

n.
  1. A mysterious, terrible, and evil divinity, regarded by some as the author of creation, by others as a great magician who was supposed to command the spirits of the lower world. See Gorgon.
    Orcus and Ades, and the dreaded name Of Demogorgon.