The Whispered One
There are many conflicting versions of the history of the dark being known as Vecna. Here is one...
Several thousand years ago, Vecna arose (probably in the regions west of Grayhawk that are now wastelands) and in his time became the mightiest magic-user in the world. The Serpent (a metaphorical term for the fundamental nature of magic) spoke to Vecna. With his lieutenant, Kas the Vampire, Vecna forged a vast and terrible empire.
Eventually, Kas turned on Vecna and the two battled. The outcome of this fight is up for debate, but Vecna lost his hand and eye.
Vecna was able to become a diety, the demi-god of secrets -- this apotheosis transformed his lost eye and hand into artifacts. However, his malign nature attracted the attention of powers more potent and fell than he and the Lich-God found itself trapped in a demiplane of darkness and horror for a time. Vecna was able to escape and made a bid for dominance over the entire multiverse with a plot involving Sigil, the City at the Center of All. This attempt was thwarted and Vecna returned to the world of Greyhawk, where he plots in darkness and gathers secrets.
Vecna was ruler of the Spider Throne in the Sheldomar Valley in Greyhawk. His people were the Ur-flan, wielders of powerful necromantic magic. His lieutenant, Kas, was a vampire lord. Kas attempted to usurp the throne from the Whispered One and managed to maim the lich-king. The Maimed god lost his hand and eye to the fabled Sword of Kas. Both Kas and the Lich-King fled and the Kingdom of the Spider Throne crumbled.
And still another...
Knowledge of Vecna came early for the Suloise migrants in the dark years preceding the Twin Cataclysms. In that period, entire Imperial Houses fled the empire, seeking refuge to the east. One house, the Kateri, found instead death and gruesome revivification. These migrants, typical Suloise, had little time for the original Flannae inhabitants of the Sheldomar Valley. They avoided what folk they could not slay, ducking from hill range to hill range, from this forest to that. Some one hundred miles south of the Rushmoors, the Kateri encountered tribes of Flan they could not displace. Had the arrogant Suel taken time to speak with the southern Flan, or even the few Oeridian tribes who even then settled the valley, they would have been warned. Instead, Lord Vecna had their heads torn from their necks and placed on spears, which his subjects stabbed into the earth to mark the southern border of his territory. As a grim joke, Vecna's Ur-Flan necromancers had the heads animated. For seven years, wildly insane, pale-faced heads stretched from the northwest terminus of the Sheldomar to the waters of the Lort, announcing the dominion of Vecna in pathetic, vaguely human rantings.
The Occluded Empire of Vecna, as it became known, served ably as a ulcer in the gut of all migrants. Oeridians flowing east from the Fals Gap had avoided Vecna’s lands by coincidence, at first, but soon learned that the lich-lord's dominion extended all the way to the northwest shores of the Lake of Unknown Depths. Despite Vecna's control over such a wide berth of land, his actual grasp did not extend far from his own Rotted Tower, said to be located in the Rushmoors, or the now-ruined town of Tycheron, along the northern banks of the Velverdyva, not far from modern Dyvers. Between these centers of depravity ranged several tribes of debased Flan, who were all too happy to carry out the orders of Vecna, or those of his most trusted lieutenant in Tycheron, Kas the Bloody-Handed. Many otherwise good-spirited tribes, however, lived under the depravity of Vecna because, as the fledgling nation of Keoland would learn in the century to come, all but subservience to the Whispered One led to certain death.
Shortly after its foundation, the Kingdom of Keoland attempted an ambitious expansion effort, supporting frontier towns to the south and west and, taking advantage in a lull of activity by the Occluded Empire, even to the north. The fate of this settlement, known as Fleeth, is best recorded by Uhas of Neheli in his Chronicle of Secret Times, a look at the scandals, crimes and cruelties of Keoland's first era. In return for the lives of all in the city, Keoland's regional burghers implored Vecna to take their own lives. Instead, the lich had the entire city gutted, the governors' wives and children executed before their very eyes, their staring heads displayed upon a vast pile of death. As a final show of "mercy," Vecna allowed the burghers to live, that they might take warning to their king.
Armies amassed in the Keoish capital. The king prepared for a great war. Though decimated by cataclysm and largely untested in battle, the skill of his troops would carry the day, despite the numbers of the Flan to the north. But what is a casualty to an emperor who can animate armies of dead with the wave of a hand? Exercises proceeded with a grim undercurrent that Winter. All might have been lost, too, had not one of Vecna's rare acts of kindness come back with a vengeance.
In addition to an unnaturally elongated life, Vecna had granted Kas with a weapon of exquisite beauty and a heart as dark as the lich-lord's soul. This blade, the Sword of Kas, whispered dark ambition into Kas' ear, urging him to make a move for the lands his master had held for a millennia or more. As armies gathered to the south, and the Ur-Flan whipped the northern tribes into war furor, Kas the Bloody Handed made his move for the Spidered Throne. The titanic struggle that followed apparently destroyed both liege and lieutenant, and a great evil was expunged from the world.
When the armies of Keoland pushed northward in a seemingly futile gesture, they found little resistance. Vecna was dead, his empire shattered. The Flan tribes now warred against each other, a primitive rabble easily brought down by a military-religious order of knights formed to do battle with a lich. Compared to that service, settling the lands that would become the Gran March was easy.
Decades later, as indentured Flan dug the foundations of the city of Shiboleth, three remnants of the battle between Vecna and Kas rested upon the floor of the Rushmoors. A hand, an eye, and a sword black as death. Their story had just begun.
The Head of Vecna
PS: pholph ... let me know if you want one, I'll print out previous "Bardic Knowledge" handouts for you.
PPS: Much of the Vecna info here was written or summarized from material by Erik Mona.