Noah's Ark, a place where people with monstrous power gathered to prove their strength against one another. There are three different types of species that inhabit the islands.

The first are the [Regulars]. Common citizen who hold zero power in terms of strength or ability, but make up the majority of the population and help make clans, cities, and guilds thrive.

The second type of species are labeled as [Noah's Chosen Ones], [NCO] for short. These are the people who were either born with Spirit Animals, or were able to fuse with Spirit Animal Eggs that are scattered throughout Noah's Ark. Only people with a certain affinity with the egg are able to hatch it and fuse with the spirit.

The third type of species are the [Demons] who come up from the Abyss to Noah's Ark on occasion and wreak havoc on the people there. A common enemy for the the people on Noah's Ark. The demons main goal is to help their Demon King Bahamut, take over the whole world and bring everything into chaos.

Raion, however, was an [Irregular]. [Irregulars] are people who are gifted with talents and skills that make them as strong as [NCO's].