All possible "End of Oerth" scenarios.

[Clistenes]

Since Oerth is supposedly doomed to destruction according to prophecies (that, or it becomes a magicless world, whatever happens first), I have decided to seek all the potential ways it can end.

Oerth-specific:

-Chainmail-The Sundered Empire scenario: Ahmut unleashes a zombie apocalypse.
-Chainmail-The Sundered Empire scenario: The gnolls of Naresh invade Ravilla and Jangir unearths and opens the Abyssal Gateways below.
-Black Moon Chronicles scenario:

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The Empire of Lynn is defeated, the hordes of Hell invade, and Methraton destroys both the hellish army and Oerth in a go, throwing Luna against Oerth.

-Gord the Rogue scenario:

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Tharizdun is released, and together with Lord Entropy destroys Oerth.

-Essence of Evil scenario: Tharidzun is released.
-Savage Tide:

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Demogorgon turns the whole world insane.

These others aren't specific to Greyhawk, but they fit there better than in other settings:

-Quicksilver Hourglass scenario: Erivatius destroys the Crystal Sphere.
-Expedition to the Demonweb Pits: If you fail, the War of Chaos and Order resumes and most of the Multiverse is screwed.
-Atropus comes.
-Father Llymic's spawn spread around all the world before somebody finds and kill him.
-Ragnorra's spawn spread around all the world before somebody finds and kill her.

Also, possibly:

-Shothotugg arrives and poisons and corrupts the world.
-Somebody opens too big a gate to the Far Realms and Bolothamogg destroys the world in order to protect the Far Realms from its taint.
-Y'chak, "The Violet Flame" finds a way to destroy all life.


I'm not counting the Age of Worms, since other gods would stop Kyuss before he did real damage, or Lolth's invasion, which was canonically stopped, or Graz'zt plan to turn Oerth into another layer of the Abyss, for the same reason.

Zargon is from Mystara, I think. Pandorym fits Forgotten Realms best. Other Elder Evils aren't really global threats.

That's what I can remember off the top of my head. Any more ideas?

[BrianDavion]

WOTC forgets you exist and you fade into oblivion? :)

[Clistenes]

WOTC forgets you exist and you fade into oblivion? :)

Yeah but we are not using that, aren't we? Too meta.

Mmmm... I wonder if they can all be combined into a single Doomsday scenario. Something like this:

Iggwilvy and Graz'zt intrigues provoke the birth and ascension of Iuz
Iuz, allied with Graz'zt, Zuggmoty and Lolth provokes the Greyhawk Wars.
Zuggmoty awakens Xhagevoxhab at Narwell.
Juiblex starts acting in Verdinica in order to counter Zuggmoty.
Lolth betrays her allies and tries her own invasion of Oerth.
Orcus tries to take advantage of Lolth's plans by sucking all the souls who die in the Sheldomar Valley with the help of Edrua.
Demogorgon tries to take the Bastion of Souls, unleash the Scarlet Tide and free Shothragot, the Aspect of Tharidzun.

Erythnul, Syrul, Pyremius and Hextor put into motion their own intriges, taking advantage of the distraction caused by the war.
Syrul and Pyremius, working on Hextor behalf, manipulate a group of heroes into killing Stratis, but they betray Hextor, preventing him from taking his portfolio for himself. Erythnul and Nerull meddle too, and provoke the Wars of the Sundering Empire. Yeenoghu and Maglubiyet join too.
Yeenoghu plans on opening the Abyssal Gates behind the Elven cities.
Nerull orders Ahmut to destroy the world, but Ahmut is just a distraction, as are Kyuss and Father Llymic and Erivatius (which he releases through his proxies, the Union of Eclipses). His real trump card is Atropus, which he knows how to lure to Oerth.

Asmodeus, displeased by the growing influence of demons over Oerth decides to take matters in his own hand. He orders Baalzephon to take control of the Great Kingdom, and orders his son Haazel Thorn to conquer Pholtus' Empire of Lynn.
Tiamat tries her own move in Elsir Valley, her plan being to ally with Maglubiyet, Asmodeus and Hextor against the demons, and starts the Red Hand campaign.

Incabulos alone among the gods guesses correctly Nerull's plan and awakens Ragnorra, hoping to counter the undead of Nerull and twist and warp the world so much that he becomes the main god.

Heroes stop Iuz several times and eventually kill him. Lolth, Orcus, Zuggmoty, Juiblex and Demogorgon all are twarted, same with Baalzephon and Tiamat, Kyuss and Erivatius.

But Ahmut, Jangir and Haazel Thorn aren't stopped, and heroes are too busy to stop Father Llymic and Ragnorra. The good and neutral gods ask to temporally adjourn their covenant so they can intervene directly on Oerth and stop its destruction, but Nerull, Incabulos, Mellifleur, Doserain, Kiaransalee, Eythnul, Falaruze and Lolth refuse (the latter out of spite), and a divine war is unleashed on Oerth.

Gods and their armies fight each other on Oerth while Undead, Pseudonatural Outsiders, warped Aberrations, demons and devils roam the world, fighting each other, hunting and killing mortals... etc.

If we take the Black Moon Chronicles's ending,

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Good gods help humans escape the world through portals, and an Epic Wizard makes the Moon crash against the world killing all the invaders (let say it is Atropus who is forced to crash against Oerth, destroying both)

(Yeah, I know, it sucks, but I have tried to put all those stories together in like five minutes).