Dungeon Master's Log - Blackstone Campaign Background, Part II - The Secret Villain

 NOTE: PLAYERS IN MY CAMPAIGN SHOULD NOT READ THIS ENTRY

 Now that I have a reason for Humans to have unlimited advancement as magic-users, etc.it is time to flesh out the world. I outline three great Human Empires (all named afterward); the Jade Empire, the Ruby Empire, and the Emerald Empire.
  The Jade Empire stretches from the war that freed Humans from slavery to the Elves through the discovery of iron by the Dwarves and on until its collapse from decadence. During its glory the Jade Empire settles the Northern and Eastern continents, finding that the Elves had beat them to each and that each had local populaces of Dwarves and Gnomes. The collapse of the Jade Empire resulted in the colonies on the Eastern continent being the only truly intact ones left.
  After an interregnum the the Ruby Empire arose on the Eastern continent. Again, the empire rose, had a period of glory, then declined and collapsed. After its fall and a Dark Age the Emerald Empire arose on the Northern continent. It followed the same pattern or growth, glory, decline, collapse, dark age.
  The campaign is set in the Human Kingdom of Blackstone, a city that survived the fall of the Emerald Empire and hope to form the core of the next Human Empire. The Jade Empire is so long ago that it is shockingly obscure to most scholars and effectively unknown to even player characters who don't have plenty of skill in Ancient History. The Ruby Empire fills roughly the same place as Ancient Greece in the West and the Emerald Empire is, roughly, Classical Rome.
  Here's the twist - the cycle of rise, glory, decline, and fall isn't the natural cycle of history, it is the fault of one person, the secret Big Bad of the campaign.
  At the height of the Jade Empire there arose a cult of Necromancers, clerics and magic-users, who worshiped the Ghoul God. They were suppressed by the Emperor but remained as a secret society. Over generations this society infiltrated the noble classes amassing great influence. At one point their leader, tA'Velistram High Priestess of the Charnel Lord, attempted to overthrow the great-grandson of the Emperor who had suppressed the cult. This coup failed resulting in the death of most of her fellow priests.
  Because of her own noble rank A'Velistram could not be executed and because of he rpower she could not be imprisoned conventionally. In the end she was taken to a remote, hidden tomb and sealed within by 6 Great Seal spells and left to die. He devotion to the Ghoul God and her own fury led her to, instead, become the first Lich.
  Over time the other wards on her tomb faltered and her hidden followers (unaffected by the Great Seals) could visit with her. This time she worked even more deeply in the shadows, rebuilding her cult and re-infiltrating the halls of power. Slowly corrupting the very fabric of society she also subtly encouraged greater mastery of magic until, hundreds of years later, she selected a promising but corrupted young man whom she trained as a necromancer with knowledge gained directly from the One Who Neither Lives Nor Dies. Eventually he came and used his arcane might to shatter one of the Great Seals and was rewarded with Lichdom. The Jade Empire, however, was already in the throes of collapse from the foulness injected by the Cult. Also, A'Velistram fears the rise of mages powerful enough to repair or even replace any of the Great Seals, so she encourages the decline. Lastly, her Master enjoys the devastation this brings.
  A'Velistram bided her time and continued to watch and influence the outside world through her agents. She repeated her success with the Ruby Empire, being lucky enough to have two of the Great Seals broken before the collapse of that empire. The Emerald Empire resulted in another broken seal, leaving only two....

  This plot point lets me dodge a lot of bullets - secretly. Why was the great Golden Age that produced Staves of the Magi and such never repeated? Someone is stopping it. Why is there such a cyclical pattern of rise and fall of empires? Someone is causing it. Why does the Ghoul God cult keep returning? Its leader can't die. Why don't the Dwarven or Elven races have empires akin to the Human ones? They can't make arch-mages so they are prevented from competing with Humans. Why is the history of the Jade Empire so obscure? So that no one can learn about her existence and how to stop her.
  It also means that, if I am careful, the Big Reveal of the real Big Bad of the campaign will be an honest shock to the players.