Reunited in their evil, Mupa had come to the aid of Sagu, threatening King Yuri with a curse upon Koguryo. In her letter, she would not state just what this terrible curse should be, but referred to an old poem , and demanded 1,000,000 coins of gold in ransom to lift this curse. Yuri sent word to Prince M'hul, who was fighting off would-be invaders from the West. No more was said about the curse at the time, though an offer of 50,000 gold coins was said to go to any who might remove the curse without giving in to the evil witch.
King Yuri would not stand for any more traitors like he saw during Sagu's invasion and declared that any citizens who shouted support for Sagu or Mupa would be branded as treasonous and banished from the kingdom.

His battle victorious, the prince received his father's urgent message, informing him of Mupa's threat. Upon his journey home, M'hul sought out the lagoon of the Sea Nymph, recalling old tales from his father of the mystical woman and her wisdom. He showed her the copy of the strange old poem and immediately, the nymph recognized it and said she might be able to unbind the curse. The stones were the key. It was part of a curse that had been used once, long ago. Someone's wickedness would cause them to turn into a creature that expressed that wickedness. The creature's heart, though, was made of stone. The nymph, eager to assist the son of old Yuri, said that she would come if these stones were recovered from the creatures to lift the curse.

The day came that Mupa kept her word, casting the curse of her threats upon the merchants of the kingdom. Suni, Beard, Walsuk - all of them, were cursed. Trapping their souls, Mupa summoned each into the Vale, the curse transforming them into monstrous violet wyrms, viciously attacking any mortal who set foot upon the bloodied land of the Vale. As the dragons attacked, Mupa pressed on with her violent bursts of fire, determined that the citizens would not save their merchants' souls. Each time she was thought dead, the trickery of her dark magic ressurected her into new life, stronger than ever.

Still, the Kogurians fought on, despite the slaughter and bloodshed. Through courage or plain madness, citizens charged forward and recovered the stone hearts, one by one, and saved each merchants' soul. It was only then that Mupa realized she could not win. Her curse had been broken. Humiliated and seething with anger, she fled the victorious cries of battle, leaving the kingdom, disgraced, for the second time.