It might be easier for me to give you the Cliff Notes of the whole campaign's backstory. I might have some of the details a little off since we wrote these 7 years ago, but the overall gist is accurate.
[sblock]In primordial times, there were four elemental spirits - stormchaser eagle, flamebringer dragon, worldshaper worm, tidereaver kraken. The dragon killed the eagle, but left its heart still beating so the others wouldn't realize his crime. The blood of the heart flows through the world, and if it's destroyed, the world would dissolve into aether. (The trillith want to destroy the heart so they can exist in a world unconstrained by physical form, but they don't get involved in the story for a while.)
By the way, the Heart is massive, about 20 feet across, and lies in the bottom of a chasm in a wasteland where no one will ever find it.
About a hundred years ago, Coaltongue was just a bold half-orc warlord fighting an elvish nation (Taranesti), and one of its big defenders was a dragon named Syana. Coaltongue captured Syana's daughter Trilla, who had latent psychic powers. He had her guarded by a bone devil. The group who came to rescue her (including a half-elf named Rhuarc -- he'll show up later) summoned a trumpet archon to help. Both the archon and the devil died, and Coaltongue lost his axe and grabbed the bone devil's femur as a club right as he was hit by a blast of Syana's fire. The mix of energies of devil, celestial, dragonfire, and psychic dragon mixed together and were drawn into that bone club, transforming it into an artifact. Coaltongue survived by teleporting out of the fireblast, and eventually realized the weapon's power. See Adventure 7 for stats on the Torch of the Burning Sky.
Time passes. Coaltongue gets more power, more allies, conquers some nations, works together with general Shaaladel (an elf, or eladrin if you're doing 4e, but not the same nation that Syana was from). Trilla's psychic powers grow stronger, and her dreams start to come alive. Shaaladel tried to find her, wanting to make a 'Torch' of his own. She was taken to the Underdark to hide her. Over time her dreams -- the trillith -- take control, lock her into a perpetual sleep, and manipulate her nightmares to create specific new dreams.
Shaaladel, unable to match Coaltongue's power, decides to bide his time and wait for the guy to die of old age.
Coaltongue gets old. Around 40 years ago, some towns along the border between Ragesia and Shahalesti start talking of rebelling. Coaltongue takes an army with the Torch to quash one of these rebellions. A young woman manages to counterspell the activation of the Torch -- this is Leska, trying to save her home town from Coaltongue's reprisal. Coaltongue could just kill her, but instead he gives her a year. Find him a way to not die of old age, and he'll spare her town. Fail, and he'll slaughter her and her town.
Concurrently, Shaaladel got pissed off at another group of elves -- in Innenotdar -- for not allying with him. He set their forest on fire and blamed Coaltongue. This is all part of his goal to make people eagerly accept him as a new ruler once Coaltongue finally perishes. Oddly, the forest fire never ends, because a trillith named Indomitability is trapped in the forest. Because of this, the local fey who are bound to the forest are trapped. One of the local fey, a man named Etinifi, escapes the forest and tries to find a way to save his people.
Leska and Etinifi meet. They learn about the Aquiline Heart, which was hidden long ago by the flamebringer dragon. Magic forbids any from finding the heart unless it is the only way to save their lives. Well, Leska and Etinifi (and Coaltongue) will die unless they find it. Still, there are trials protecting the heart, and things get bad. Etinifi betrays Leska, leaving her to die so he might have a chance to escape. He becomes immortal and escapes. Leska, basically dead and just crawling with willpower, manages to get to the heart and save herself. By the time she gets out of the cave where the heart lies, Etinifi is gone.
She returns to Coaltongue, takes him to the heart, makes him immortal. They return to her home town, and discover that Shaaladel has taken it upon himself to quash the rebellion, "as a sign of good faith." (In effect, Shaaladel heard Coaltongue has managed to thwart death, so it's a good idea to get back on his good side.)
Note: Shaaladel is NOT immortal. He's just an elf/eladrin, and they live a long time.
Leska - having nearly died, been betrayed by a friend, and then learning all her suffering was for naught -- basically loses all empathy and human decency. Coaltongue sees her value, though, and recruits her with the promise that when the time is right they'll destroy Shaaladel.
Fast forward to a couple months ago. Leska's original desire for revenge against Shaaladel has turned into a general belief that she should just rule over everyone. She has made contact with some trillith, and just sees them as a new weapon to use, not realizing what their plans are. She has a bunch of loyal inquisitors, and has built a super-weapon -- the Scourge. It's basically a large magical focus that takes in power from the suffering of hundreds of mages in an underground gulag, and uses it to strengthen spells used by its controller. Oh, and in the middle of that underground prison is Etinifi, whom Leska keeps in a constant state of agony (thanks to the trillith named Agony).
Leska tracks down some of the best assassins (two drow, and the half-elf Rhuarc). In a nice bit of symmetry, she waits until Coaltongue is out trying to quash a rebellion. She sends in the assassins (who don't know who hired them). They behead Coaltongue, stick a spike in his heart, and place his body in a casket that kept the head from reattaching. So he's still immortal, just currently unable to come back to life.
Thing is, Leska didn't know about Rhuarc's personal grudge against Coaltongue. Rather than hand over the Torch, Rhuarc decides to damage it and hide it. He uses some magic to extract Trilla's essence from the Torch, leaving it malfunctional. Since the Torch is the big teleportation artifact, this causes an imbalance, so now teleporting burns you up. The assassins hide out in the ruins of a Taranesti city, and Leska kicks off a war trying to find the Torch.
So . . . here we are now.
Leska wants to find the Torch so Shaaladel cannot oppose her. Shaaladel wants the Torch so he can beat Leska. The trillith have a few of their number helping Leska, but that's just so they can better discover how to locate the Aquiline Heart, since they want to end the world. The party starts off in Gate pass, which is stuck in the middle.
Eventually the party finds the assassins in the city where they're hiding. (It's haunted, and has a lot of protection against divination.) The PCs might bring Coaltongue back if they want to complicate things, or just leave him in a box. But they learn that if they want to stop Leska, they have to find the heart. They eventually will attack the Scourge (a fort with a superweapon, built over a prison), and rescue Etinifi, who can show them the way. Except Etinifi's crazy, and like the trillith he kinda wants to destroy the world.
You end up with a climax where Leska goes back to the Heart and tries to perform a spell through it that will turn all her enemies against each other; the party goes there to stop her; the trillith go there to try to destroy the world; and Shaaladel probably goes there pretending to help the party but intending to betray them.
Oh, and there's another villain who builds a giant airship but honestly he is probably one of the weaker parts of the campaign.[/sblock]
I hope that helps. Good luck tweaking things for your campaign.
