The potion that can transform into an iron dwarf is called the Iron Boot Refining Potion. You need 10 Du Ya relics to buy.

The NPC purchased by the tribe is located at the crash site of the Gromia airship. There is a flying spot under the Guardian Library. This is the mission line of the tribes in the stormy mountain area.

The alliance bought NPC NPC of an explorer association in Frostburg.

Remember to clear the task before buying.