Looking for scenario suggestions
TLDR: Sacred artifact hammer got corrupted when it was used to kill a high priest and then used to do bad stuff. To fix it, PCs must venture into a dreamscape within the hammer populated with the souls of the hammer's victims along with the murderer who was killed while holding the hammer. Looking for 3-4 dreamscape scenes that the PCs must somehow resolve to put the souls at rest.
Background: Torag crafted an artifact hammer which was given to the dwarven people at the beginning of the Quest for Sky. It was used to guide the way to the surface, to remove obstacles in their path and to forge arms and armor to outfit the dwarves for use in the quest. The last obstacle before reaching the surface was a huge vein of mithral blocking the dwarves' advance. The hammer was used to crumble the surrounding stone to reveal the sky above. The massive mithral ingot left over became the sacred anvil at the center of a cathedral to Torag in which the hammer was enshrined. The hammer, anvil and a dragonfire-forge were used in tandem to forge epic arms and armor which were used to found the kingdom of Koldukar. About 1,000 years later, giants and orc hordes started to encroach threateningly on the borders. The dwarf king's princely brother tried to convince the king that the hammer should be used to subjugate the giants and orcs so that they could serve the dwarves and build an empire. The king disagreed so the prince took it upon himself to go to the cathedral and instead convince the hammer-bearer high-priest himself. The high-priest told the prince that the gods didn't want the chosen people to achieve greatness through slavery.
The dwarf prince grew angry, snatched the hammer and struck down the high-priest with it before fleeing with it. This blasphemous act made the dragonfire-forge grow cold, the anvil turn to black iron, the hammer to become cursed, and all the magical arms and armor it had crafted in the past 1,000 years to lose power. The murder, theft, and despoilment, along with the loss of magical arms and armor throughout the kingdom severely weakened Koldukar. Shunned by his people, the prince fled into the mountains where he was cursed by the gods to become a fire giant. Seeing this as a sign, the prince used his new form and the power of the hammer to begin subjugating the giants as he'd originally planned and use them to seize the throne from his foolish brother to (say it with me) Make Koldukar Great Again! A pseudo-civil-war broke out, but even demoralized and underpowered the dwarven legions managed to defeat the cursed prince's giant forces. The prince, in his fire-giant guise, slew and in turn was slain by dwarven legionnaires. Unfortunately, Koldukar was left weakened by these shenanigans and the orc general Belkzen took advantage of it to raze the Koldukar to the ground.
Now the PCs have the hammer and have seen evidence that the souls of the righteous dwarves slain with the hammer are somehow contained within it. On occasion, ghostly dwarf legionnaires have been called forth from it to bolster the party in times of need. Unbeknownst to them, the soul of the high-priest as well as that of the cursed prince is also contained inside; forever wrestling for control of the hammer. The PCs, who are all dwarves themselves, are about to set foot inside the long-abandoned cathedral where the iron anvil and cold forge are. I was thinking that this might serve as a catalyst to draw the PCs into a mindscape within the hammer in which the souls are trapped in a stalemate. I'd like to present the players with a few scenes which introduce these ancient souls as fully-fleshed characters and possibly showcase some of the key moments from the story above; all with the goal to have the PCs resolve the conflict, remove the curse from the hammer and restore it to a state of grace. I'm also considering the notion of having the soul of the high-priest grant the hammer sentience.
Any suggestions for scenes or events within this scenario which the PCs must favorably resolve and what powers the uncursed artifact hammer could possess afterward? C'mon guys! We're nearly 50 sessions into this scenario and I want to make it memorable.