The Oni Xungo was the commander of Cuelebre's draconic army in the third age and the prime servant of the Xorvintaal dragon. As per the rules of the Great Game of Xorvintaal, Cuelebre imbued him with a tremendous amount of her power. This made the already formidable ogre mage nigh unstoppable on the battlefield. Xungo delights in the suffering of humans and once permanently blinded every person living in the city of Mungu with his bare hands as part of the terms of their surrender. He was also known to personally butcher prisoners of war and feed them to his army.
Eventually, he was imprisoned in the 6 demon bag, due to the noble sacrifice of the hero Kie. This trapped a great deal of Cuelebre's power away, forcing the godlike dragon into a mortal form.