Agito is technically a group, though its members tend to act independently more often than not. Nedrick, the former seventh scion of Alberia, gathered the six other members of the "group." All seek to upset the established order in some form: Volk lives to kill the strong, Kai Yan lives to kill the weak, Ciella wishes to dismantle the church, Ayaha and Otoha simply wish to be free, and Tartarus wishes to destroy the world.
Nedrick gathers them together, giving them power through masks. These masks appear to be made from black mana, destabilizing them further. While they are initially left to their own devices, Nedrick summons them as a group upon the defeat of the Other by Euden. They assist him in kidnapping his twin sister, Zethia, and work to waylay Euden and his party as they travel through North Grastea. They then assist Nedrick in assaulting the Fairy Kingdom in order to capture the Dawn Shard, an immensely powerful stone, to reforge Nedrick's dragonpact with Bahamut.
Battle vs Adventurers (Final Fantasy XIV) (by Leolab)