"Hell is your life gone wrong."
Inside the cave, the party found themselves in a gray waste, people milling about in and out of hovels as a great wailing sound originated from a great distance. Moving forward for several hours, they found themselves lost in an abyss of gray buildings and lost people, each pleading for signs from their gods or family that make be looking for them.
"They've been waiting a long time for gods that aren't coming." It was a familiar voice that identified what this place was. Vedrin, lost to them many weeks before, stood alive… no, not alive… bearing the marks that caused his death. "Don't worry, " he said, "it doesn't hurt anymore. I scarcely notice in fact." Then he looked them over as one of them blinked and said, "but you're not here to wait with us. …you are still alive."
The dead, he told them, do not close their eyes.
The accusation brought a city of the dead's weight in pleas, but Vedrin led the party to safety, through twisting streets, until they reached a great spire constructed from bones, nested at the heart of the City of the Lost.
"You get good at hiding when they're looking for you here," he explained. Vedrin died without faith, and as such it was his destiny to be buried in the Wall of the Faithless for all eternity. The guards, tanar'i loyal to the god of the dead, would grind up mortar from dead too young to understand faith, and build a wall from their undying souls—including his.
Assisting one of the Faithless in diverting the guards, he explained, earned the same fate, which meant the party would need to step lightly. They were now at risk themselves of never leaving.
The guards didn't need to find them, however. The Drow, who value freedom and power above all else, declared that this fate was wrong. All they needed to do… was kill a god. Entering the castle yards, they found themselves among a host of tanar'i who challenged them for their impudence. The fight was short and surprising, as one of the party extended their hand, and eldritch flame danced from her fingertips, exterminating the first tanar'i in a puff of black smoke.
Tanar'i, who desire power, but also existence, wisely took to wing and fled, as the party turned their attention on a member of their own who had exhibited the powers of the gods, which they had seen in Tantras a few nights before.
Deciding to "figure it out later," the party entered the Castle of Bone intent on slaying Myrkul, but they found him already gone, and the tablet claimed by another. In that moment, on the mortal plane Cyric killed Myrkul and his gray waste began to fall apart. In a pitched battle through the streets with the released tanar'i now feasting on the souls of the dead, the city itself breaking apart as the Castle of Bone collapsed under its own weight, the party miraculously found itself back on the ship.
The party completed its sojourn to Waterdeep in time to defeat the last vestiges of Bhaal's army, now under the control of one of their own turned against them. It was when she was herself slain in the pitched battle that Cyric dashed by with the tablets and ran headlong for the celestial stair. It was the booming voice, "ENOUGH!" that drove the entire world to its knees.
For their part in ending the Godswar, the party were elevated to godhood to build their dark Seldarine, and on their arrival they saw a curious sight… acres of unclaimed stone pillars, obelisks dedicated to as yet unknown gods, whose symbols of authority were as yet unwritten.
And beyond the sight of all, the Hidden One knelt to an even greater power as he declared, "The Realms are secure."