Old Scratch
Long, long ago, there was a great devil, known as the Lord of Light, who ruled over the denizens of the Netherworld. The Lord of Light had many servants, but among his least was his pack mule, Old Scratch. Old Scratch was envious of the Lord of Light's power, and began to practice the dark arts to search for a solution. Aided by the whispers of a fearsome power, Old Scratch was able to locate and steal the Lord of Light's soulgem, trapping the devil in his power, and devoured his former master. With the blood of a devil lord now flowing him, Old Scratch became a mighty evil in his own right, and began to procreate, spreading his powerful, unnatural offspring throughout the Netherworld.
Many years ago, he attempted to manifest into the material realm, but was stopped and returned to Hell by a coalition formed from the priesthood of the Nine Goddesses. In his rage, he turned back to the dark power he had visited before, and with its help, sought to once again work his way back into the world.
However, before his plans could come to fruition, that fearsome power, Despedia, was slain by a brave band of warriors [prior to the opening of the 9th gate for campaign timing]. Old Scratch himself was nearly killed as he attempted to enter the material realm too soon, but his own power preserved him. Now, several decades later, Old Scratch is once again bringing his plans to fruition in the material realm, aided by the most powerful of his foul brood. With their help, he is manipulating the people and the fey on Kaia, sowing the seeds of their cult and readying the planet for a plunge into damnation.
Old Scratch's existence is unknown to most; those who have heard of him are primarily those who he has psychically contacted, with promises of great power and reward for their service. Those with innate magic, especially the fey, are particularly vulnerable to his suggestions, as their minds more naturally open to magical influence, and most lack the discipline and determination needed to resist his influence. Those few elders of the priesthood of the Nine Goddesses who are privy to his existence keep it secret, lest the common folk be exposed to his malign influence, even indirectly.