Keraptis

Keraptis was an evil wizard who rose to power well over a millennium ago in the valleys of the Sword Mountains. He brought local warlords under his thumb with gruesome threats - threats that were fulfilled just often enought to keep the leaders in line.
Under Keraptis' overlordship, the influx of monsters and raids from the wild mountains decreased markedly, dwindled, and then almost stopped. Seeing this, the populace did not put up much resistance to paying the wizard's heavy taxes, especially when stories were circulated of what heppened to those who balked. Any nobles who protested disappeared in the night and were replaced by the next in the line of succession, who was usually inclined to be more tractable than the previous lord.
Gradually, as dissension was stilled, the taxes and levies became even more burdensome, until eventually the wizard was taking a great piece of everything that was grown, made, or sold in the valleys, including the newborn young of livestock. Around this time, numerous reporst arose in the land concerning sudden madness, demonic possessions, and sightings of apparitions and undead. Furthermore, monstrous incursions into the settled lands began to increase as raiding parties of humanoids assaulted villages, and evil and fantastic monsters appeared from nowehere to prey upon the harried peasants. At the height of this unrest, Keraptis's tax collectors came forth with word of a new lefvy: one-third of all newborn children were henceforth to be turned over to the wizard.
That edict tuned out to be the tipping point. As one, the people rose up to overwhelm the wizard's lackeys and marched on his keep, where, led by a powerful and good cleric and his ranger acolytes, they destroyed Keraptis's final guardians. The great wizard barely managed to escape, accompanied only by his personal bodyguard company of deranged and fanatical evil gnomes.
Keraptis fled to the cities of the south and west, but wherever he went, his reputation preceded him, and he was unable to stay anywhere for long. Once again moving north, he came to the shores of the Lake of Unknown Depths, where he heard tales about haunted White Plume Mountain. After investigating further. he at last found the refuge he was looking for in the tangled maze of volcanic tunnels beneath the cone. He and his gnomes vanished into the shadow of the Plume, and humankind heard no more of the evil wizard.