The temple is a generic temple like many in regions that have diverse travelers passing through all the time, with shrines to many gods and an emphasis on whichever ones the locals happen to prefer.
The Warriors greet Ironbeard Grunnson, a dwarven merchant working with the soldiers in the fort on supplying them for their war...
"My father was Grimcrag Grunnson, son of Ungrun Grunnson the Grimly Glum. After his death in the dungeons below us, I became lord of our clan. He was a great warrior, bold, and some would say foolhardy. He led a party of like-minded heroes into the ruins in search of treasure. Stories are told of their glorious quest in the forgotten halls of the dwarf under-realm. They vanquished hundreds of orcs and their kind in the darkness, killing many minotaurs, dragon ogres, beastmen, and creatures of Chaos as they pressed grimly onwards.
In the bowels of Karak Azgal, they discovered ancient passages not of dwarven origin, possibly delving to the mountain's very roots. My father thought they were what he had been searching for, although what he hoped to find down there, I know not. But it was in those cursed halls that he met his doom, buying time for his companions to escape with their lives. Beset by overwhelming odds, he held out against his foes for many hours, the bodies of the slain building up into a rampart of scaly flesh before him. Wearied and battered, bleeding from a hundred wounds, he fought on, his deathsong echoing through the lonely tunnels beheath the earth. His companions fled, his song following them. Finally it stopped, and they knew that Grimcrag was no more.
When his companions met my grandfather upon their return, they wept as they told the tale. My grandfather grieved loud and long, tearing his beard as he mourned for his son. His loss, however, was increased twofold, for my father carried with him the legendary Grunnson Axe, a magical weapon of great power. The thought of this great dwarven artifact in the hands of the evil creatures that now held sway over Karak Azgal must have been too much for the old man to bear. He put on his battle gear and went out toe reclaim the axe himself. He was never seen or heard from again.
It is my duty to resolve this, but I'm no fighter. Which is why I'm hiring you. Find out what happened to my father and my grandfather. If you can bring back the axe, there will be a special bonus as well. And I know a secret route to the entrance that my father marked with his rune, so we can get around the normal tolls, so you can keep any treasure you find for yourselves."