High Priest of Dreamworld
On the Plateau of Leng in Dreamworld rises the rude shape of a wide and massive building with no windows, surrounded by a guard of monoliths. This is the remote and prehistoric monastery that is the dwelling-place of the indescribable High Priest of Dreamworld, who covers his face with a yellow silk mask. Based on geography, he might not be human but a moon-beast. (???) Check into similarity to the Veiled Prince of Khosana in "Lalla Rookh" as well as the Veiled Thing of "The Slayer of Souls" by Robert W. Chambers who himself makes references to Thomas Moore's poem.
[The Dream-Quest of Unknown Kadath - H.P.L.]
See also: moon-beast