The Cubera Mine was the first mine ever developed in MU. Miners claim that monsters began appearing after a group of people who worshiped Kundun held a ritual at a nearby altar. At first, only a couple of monsters appeared, but as time passed, the number of monsters grew out of control. For this reason, the mine was closed and abandoned for a long time. However, due to shortage of gemstones and minerals, warriors can be found fighting these monsters infesting the mine.