Mondaloa, the City and the God
Mondaloa is the god of Rest, Peace, and Death. He shares his name with the city of Mondaloa, which he rules via his church. None of this prophecy, oracle, fortune-telling business. Mondaloa tells you when something needs to be done. And Mondaloa is all business.
And Rest, Peace, and Death are Mondaloa's business. Rest occurs on its own, and he urges his followers to seek it out and to provide it. Peace needs some coaxing to occur, and in this he is always opposed by Avenglass, the god of war. But it is Death that requires most of his attention. Undead rise from their crypts, and must be put back in, and the proper honor must be given to them. Tombs are continually defaced by loot-seekers and vandals, denying the dead their rest. Restless ghosts must be appeased, and reconciled with their living families so they can rest.
The City of Mondaloa is auspiciouslly placed: beneath it lies over a hundred miles of crypts--proof of hundreds of years of honoring the dead. Mondaloa, the god, believes that since crypts will be our homes for eternity, they should be monuments of beauty and peace. For this reason, the crypts resemble a palace, while the city above is as dirty and grey as any other city in the world.
These crypts are sacred, and only the most desperate of men (or the most experienced of thieves) traverse them. The living have no place in the crypts, and where they trespass, the dead may rise and slay the intruder in righteous, just wrath. And beneath the crypts of Mondaloa is another city--the fallen city of Kesh, conquered by the forces of Mondaloa half a millennia ago. It was a great victory, until certain forces stirred in the conquered city. These dark forces torment the sacred dead buried beneath Mondaloa, painfully rousing them from their sweet slumber. And now hordes of anguished dead slouch up from the alabaster halls of the crypts. They shamble up from subterranean galleries and through sweet-scented gardens of delicately carved stone flowers. They crawl from the white halls into the grey, smokey streets of Mondaloa, where they seek to destroy the living in their blind rage.
After years of peace, the various knighthoods have had to reform and expand to deal with this threat. There are many brotherhoods, and most are civic- and not martial-focused. But the martial orders concern us the most, for the purposes of this discussion. Some seek to destroy witches. Others demons. Others heretics. Others police the other knighthoods. Others delve into the lost city of Kesh, seeking an end to this stirring that they may end what is anathema to Mondaloa.
When a ghoul rises howling in the street, the faithful fight together to destroy it. Once destroyed, they hold hands around the corpse, and sing hymns. A tear may roll down a cheek. This was their ancestor. What darkness could drive him against his own people? After the corpse has been reconsecrated and bound in holy wrappings (scriptures of Mondaloa, so that he may sleep peacefully once again) it is brought back down into the catacombs, hopefully to the very tomb where it was first laid to rest (after it has been identified), and more prayers are said.
Larger attacks are rarer, but they can become much, much more gruesome. Afterwards, these areas resemble a war zone. But even after tragedies such as this, the proper respect is shown for the dead--both the ancient and those that are still warm.
Some knights descend into the crypts to fortify the dead with holy scripture, that they may not be disturbed again. Most return. Fools talk of moving the crypts. But the wise know the truth: that the city of Mondaloa was built for the dead, not the living. Those below ground outnumber the ones above it by twenty to one.
Thieves: Descend into the catacombs and return a macguffin that has been stolen from the Church of Mondaloa. The thieves know the catacombs much better than the PCs, and constantly lead the PCs into situations where they may easily enrage the sleeping dead. Combat against the undead is complicated by the presence of members of the Church, who condemn any defacement of the dead, aggressive or not. Cutting up a zombie must be followed by long rituals that slow the party's travel. After the macguffin is recovered, the way back is blocked, and the party must find a new way back to the surface.
Reconsecration: The party must accompany a cadre of knights from a shorthanded brotherhood as they descend into the crypts, recover some bodies, and bring them to the surface for reconsecration. The crypts always hold danger, but remember that the bodies must be treated respectfully. During the reconsecration ritual, the party and the knights are attacked by inky creatures that ooze up from the floor and pool on the ceiling, where they attack with their long, lashing tails. Upon defeat, they disappear into puffs of black ectoplasm. After the ceremony, the reconsecrated dead will begin walking in a line back to their respective tombs. In this state, they are incapable of anything except walking forward. However, if disturbed, they will become enraged, and the ceremony must be reperformed. This is complicated by the presence of another adventuring party who has only been in Mondaloa a few hours, and sees the line of shuffling dead as (a) animate undead who are probably evil, and (b) a long line of golden necklaces and rings.
Purification: The party must descend through all four layers of catacombs (each corresponding to a different age of Mondaloa, with different architecture and themes) and into the lost city of Kesh. This is complicated when the party stumbles upon and is attacked by black-tongued cultists of Zala Vacha (a collective composed mostly of gods who are no longer worshipped) and their demons. Deep in the crushed city of Kesh, the party explores the (now sideways) palace of Kesh, and encounter a vestige of Urzalon, a (now destroyed) dracolich and the last king of Kesh, who seeks to destroy the party. During the fight, Urzalon roars things such as "You should never have come down here! I'll destroy you before I let you fall into his hands! This is a kindness! Do you know what he does to wizards such as you!?" Deeper in, they encounter a veritable city of shuffling undead, firing up forges and slowly hammering out weapons of war. And even further down, the party encounters more slouching undead, arrayed in an ancient church of some kind, performing a profane ceremony in the worship of a demonic dragon called Demodius, half-brother to Urzalon and the ultimate betrayer of Kesh. (It was Demodius' betrayal that felled the city of Kesh, not the armies of Mondaloa.)
Although he was defeated, and has no way of leaving hell, Demodius has nevertheless opened a portal beneath a sacred lake and now sits halfway through the middle (a loophole of hell, if you will). Here, he screams in rage and beats his black wings against the icy waters, which have been frothy and stormcapped without pause for nearly 200 years. From here, he sends he rage up into the city of Mondaloa, enraging the peaceful dead and committing this great blasphemy againt Mondaloa, the god who stole his victory so long ago. Many of the dead have already fallen under his spells, and soon he will have his army, ready to crush the pitiful forces above. Soon, Demodius will have his city, and a new center of evil and undeath will sprout on the surface of the world.