Saga Region is a region where several tribes of three factions are located: the Fuu faction, the Voda faction, the Tehre faction. Some famous heroes lived there, as Seida, from 
Holy Guard, Nina, from 
Scarlet Flame Guard, and Tina and Mocca.
Saga Region is the main location where Chapter of the main story takes place. See below where Saga Region is.
See all the Units from Saga Region here.