Since he is the most popular Ancient One in the game, I figured my fellow players, especially those who appreciate theme and mood, might enjoy reading a bit about Ghatanothoa. From Wikipedia:
"Ghatanothoa is a Great Old One and the first born of Cthulhu. It is a huge, amorphous monstrostity which is so hideous, that anyone who gazes upon it (or even a perfect replica) is petrified into a living mummy. The victim is permanently immobilized—the body taking on the consistency of leather and the internal organs and brain preserved indefinitely—yet remains fully aware. Only the destruction of the subject's brain can free it from its hellish prison, though the unfortunate is likely to be incurably insane long before the welcomed release.[1]
Ghatanothoa is currently trapped underneath Mount Yaddith-Gho in sunken Mu. He was brought to Earth from the planet Yuggoth (Pluto in Lovecraft's fiction) by an ancient, alien race, possibly the Mi-go[2], who built a colossal fortress atop Yaddith-Gho and sealed Ghatanothoa inside the mountain beneath a large trapdoor. Ghatanothoa was worshipped by the ancient Muvians, who both feared and respected him because of his ability to turn any humans that beheld him into living, thinking mummies.
Many attempted in vain to defeat Ghatanothoa; most notably T'yog, the High Priest of Shub-Niggurath, whose story is recounted in Friedrich von Junzt's grimoire Unaussprechlichen Kulten or Nameless Cults (Robert E. Howard's answer to Lovecraft's Necronomicon). T'yog created a scroll that was supposed to protect him from the petrifying effect of gazing upon Ghatanothoa. But T'yog was defeated after Ghatanothoa's priests stole the scroll and replaced it with a fake one (however, this was not done out of praise for Ghatanothoa, but rather to protect the populace from its wrath had T'Yog failed). This occurred in the Year of the Red Moon, which is 173,148 B.C. according to von Juntz.[3]"
Speculation on his Stirring in Slumber ability: Since a perfect reproduction of Ghatanothoa will also petrify a victim, I believe that his Mi-Go and Lloigor worshippers have been carving his visage in various places in Akrham and the surrounding towns as an act of reverence and in celebration of his coming. When you seek out information about the Mythos, you naturally run the risk of encountering one of these reproductions of Ghatanothoa's visage. It's easy to envision his face carved on a wall in the Black Cave, on a tree in the Woods or Unvisited Isle, or even as a three-dimensional representation cut into the text of the King in Yellow or Old Journal.
Incidentally, the Lloigor are NOT simple reptiles by any means. From Wikipedia:
"August Derleth and Mark Schorer originally created a being called Lloigor as one of the Twin Obscenities in their short story "The Lair of the Star-Spawn" (1932). Lloigor and its brother Zhar were typical pseudo-Lovecraftian tentacled monstrosities, two more additions to the fiendish fictional menagerie known as the Great Old Ones. Derleth referred to Lloigor in several other writings, "The Sandwin Compact" (1940) in particular. It was apparently a wind elemental and possessed the ability to somehow draw its sacrificial victims to it, perhaps through teleportation.
Colin Wilson borrowed the name for "The Return of the Lloigor" (1969), but his creatures are very different from Derleth's creation. The Lloigor[1] take the form of invisible vortices of psychic energy, though they may sometimes manifest themselves as great reptilian beasts, akin to the legendary dragons. In the distant past, the Lloigor came from the Andromeda Galaxy to the continent of Mu and used human slaves as their labor force. When their power dwindled, the Lloigor retreated below ground and left their former slaves to their own devices. Eventually, these early humans migrated from Mu and populated the earth.
In modern times, the Lloigor are too weakened to pose any real threat to humanity. Nonetheless, they can draw psychic energy from sleeping humans in nearby towns or villages—the victims so affected awaken feeling drained or ill, yet regain all lost vitality by nightfall— with which they can perform strange, preternatural feats, such as causing mysterious explosions or altering the flow of time.
Most other authors use the Wilson entities rather than the Derleth and Schorer conception[citation needed]. In Robert Anton Wilson's Illuminatus trilogy, the term appears to be synonymous with Great Old One—for example, H. P. Lovecraft's creation Yog-Sothoth is called a lloigor.
Scottish comics writer Grant Morrison used the Lloigor as the primary villains (possessing the bodies and minds of various superhumans on various parallel earths) in his Zenith series for 2000 A.D.. However, once again these Lloigor are a departure from what went before. They are referred to as many-angled ones (possibly the first use of this moniker) and appear to be entities from a reality with more dimensions than our own, so that disconnected bits of them (tentacles, eyes) appear to 'float' around the scene. The many-angled ones have appeared in other works since, most notably Charles Stross's The Atrocity Archives, but it's not clear if these many-angled ones are considered to be related to the original Cthulhu Lloigor.
In the 1975 The Illuminatus! Trilogy, the lloigor are mentioned as the gods of the aboriginal natives of the People's Republic of Fernando Poo, as well as the original gods of Atlantis.
Lloigor are also mentioned in The League of Extraordinary Gentlemen: Black Dossier as inhabiting Yuggoth and being in conflict with the Blazing World. Nyarlathotep is sent by the Lloigor to negotiate a truce at the end of the comic."
- Mariana the ex-nun cultist