Chthon
The entity: Chthon is one of the Elder Gods who first materialized in Earth's biosphere shortly before mankind appeared on Earth. He and his sister Gaea were among those who inhabited the land masses. When Chthon suspected that they would be supplanted by the newer gods, he inscribed a parchment with the mystical knowledge of the world he has amassed. This parchment would later be known as the Darkhold. Through the Darkhold, Chthon has an indestructible medium through which to manipulate Earthly pawns.
Chthon possesses a mastery of mystical forces on a scale that defies description. In the dimension where he now resides he has absolute control over every aspect of that dimension's reality. His major limitation is that he cannot freely teleport between dimensions because it takes such an enormous rift to accomodate the massive magical force that dwells within him. He cannot travel to Earth without the most elaborate of preparations due to the exhaustive magical screens around Earth first erected by his sister, now known as Mother Nature, and reinforced by Earth's multitude of sorcerers over the millenia.
Entreating Chthon is almost the same as entreating the Darkhold, except his powers are far greater. The difficulty is that he is most definitely evil, and there is a 20% chance that he will use the entreating individual as a host body. When this is done the Psyche of that character becomes Un(100) and he is able to cast any non-"white" magical spell.
The spells: Unrevealed; it is presumed that Chthon has access to any spell not specifically linked to order.