Belialuin was a city populated by wizards, who remained neutral during the Holy War between the Goddess Clan and the Demon Clan. When a miraculous girl who possessed the Infinity power was born among them, the news soon spread in the realms of the goddesses and the demons and both parties tried to put the girl on their side to tip the balance of the war in their favor. The people of Belialuin opposed this, claiming that both the girl and her power were their property. However, against the wishes of her people, Merlin decided to negotiate with the gods of both clans, the Supreme Deity and the Demon King, and said she would follow the one who gave her the best blessing. Merlin somehow managed to deceive both gods to renege on them by accepting both blessings. Furious, the two gods unleashed their anger against Belialuin, cursing her with a fog of death for a thousand days and destroying it with a rain of fire and lightning. Merlin was able to escape unharmed, becoming the only survivor of Belialuin.
The Ten Commandments are aware of Belialuin history, and express shock that Merlin could be from there calling her "that survivor", implying some sort of great disaster befell it which only she survived.
- The name Belialuin appears to be stemming from the term "Belial" (or "Beliar") that first occurred in the Hebrew Bible, and later in Jewish and Christian texts to refer to the Devil personified.