Eidolons, sometimes called Great Beasts by the Al Abassi tribes, are creatures of tremendous primordial power who exist all over the world. They're feared and revered by lesser creatures for their vast power and are oftentimes mistaken for being gods descended from the heavens to protect their creation. In a sense, this is indeed true, for some Eidolons are indeed defenders of the natural order and the world as a whole; although most of them could care less about the myriad of creatures that inhabit it. Among the most well-known of Eidolons are Leviathan, Shiva, Ifrit, Ramuh, (Summon) Fenrir and Bahamut.
Scholars believe that the sheer number of Eidolons governs the flow of Aether, mana and energy that permeates the world, a theory supported in that Eidolons are beings, not made of flesh or bone: but raw energy, mana and perfectly aligned aether which composes a "vessel" capable of housing untold power. Indeed, they've come to be seen as not merely being the worlds defenders but in essence being the very thing that keeps it stable and liveable. Thus, they're not as much supernatural creatures of awesome power, as much as they are aspects and avatars of elements, ideals and purposes molded into an appropriate shape; and it has been inferred by Summoners¨...