Children of the Full Moon are a select group of humans blessed with a formula that allows them to convert aer into energy and use powerful spells without the use of a blastia. However, the Children of the Full Moon ultimately consume more aer that even the most potent of blastia, making them, as the Entelexeia refers to Estelle, an "insipid poison" to the world and its balance. As a result, the land's aer krene become stimulated, eventually reproducing an excess of aer that spurs chaos in the surrounding areas. Similarly to blastia, this "abuse" of aer empowers the Adephagos, a monstrous non-sentient being dubbed the "Cataclysm".
According to records of the ancient Geraios Civilization, only leaders possessed Child of the Full Moon powers in the past. These special individuals used their power with little thought, though they were warned by the Entelexeia of its adverse properties, analogous to that of blastia. When the Adephagos eventually arose as a result of the abuse of aer, the Children of the Full Moon lamented their negligence, sacrificing their lives to power Zaude, an extremely large barrier blastia that could protect the planet from the Adephagos, and ensuring that blastia use be monitored in the future so that such a threat would not engulf Terca Lumireis again. They established the Empire in order to accomplish this. In the present day, Estelle, a member of the royal family, is one of the few remaining Children of the Full Moon, defined by their pink hair and mysterious spellcasting abilities.
In the PlayStation 3 port of the game, an optional town called the City of the Waning Moon, which rests at the bottom of Zaude, within the same realm as the Necropolis of Nostalgia, serves as a home for the souls of the Children of the Full Moon who have sacrificed their lives for the sake of the world's protection. The city is detached from time and reality above, and the souls speak in a broken, sometimes incoherent manner. The king of the Children of the Full Moon, Ohma (オーマ Ooma?), is imprisoned within the city as the result of a conflict ages prior, in which the Entelexeia and ancestors of the Children of the Full moon worked together in sealing Ohma away for 1,000 years. He has only managed to remain alive for so long due to a drug known as amurita (アムリタ?), given to him by the king of all Entelexeia, Spiral Draco, who also resides deep within the city.