Dondakan has spent 18 years of his life attempting to open a seemingly impenetrable rock in the Keldagrim south-west mine. While he had many dwarves helping him at one point, they have all since left, leaving him alone in his work. He now spends every bit of money he can dredge up in an attempt to open the rock.
Dondakan has tried many different methods to break the rock, such hitting it with a pickaxe, shooting it with several types of cannonballs, and kicking it with granite boots. None have been successful, and the cost has taken a toll on him.
Dondakan has 6 un-obtainable items - all cannonballs from bronze to rune except steel.
It is unknown why he would try bronze or iron cannonballs, as they would obviously not have as much of an impact as standard steel cannonballs. It is possible that he predicted that a massive number of shots would be needed to crack the rock and was attempting to save money. It is also possible that Vincent Van M (the developer who created this NPC and the Between a Rock quest) intended to emphasize how hard the rock was to break while making a humorous observation based on the player's inability to smith cannonballs from every tier of metal available in the game.
Players may attempt to buy his granite boots, but he will not sell them for any price offered. If players have granite boots in their possession, they will be able to engage in unique dialogue when speaking to him.