From a particularly dogeared copy of ‘Research Team Guidelines’ by Archon Niniri Niri.
In order to discuss aetherytes one must begin with the fundamental nature of the world. The world is composed of two dimensions, the corporeal world and the aetherial one, sometimes referred to as the lifestream. When something, or someone, in the corporeal world is destroyed or dies their aether passes into the lifestream and when new life is born or new matter formed, it draws from the lifestream, creating a cyclical system. These two worlds are close to each other at some points, and further at others. In areas where the two worlds are close, a living creature may reserve their sense of will while discorporated into a form of pure aether, a phenomenon that is essential to the techniques known as teleportation. Via the application of magics one might achieve this phenomenon, but without caution the now formless figure might be lost in the lifestream. This is when aetherytes enter the scene, colossal crystals of condensed aether which exist in the corporeal world but beam their light across the aetherial world. These aetherytes typically had to be constructed in areas that exist close to the lifestream to function, which conveniently aligned with inhabited regions as areas that that two worlds are close in are also typically home to dense life and material richness. Sharlayan innovations have since allowed them to construct more flexible aetherytes, able to be placed in less close areas.
The Aetherytes of Eorzea
Aetheryte technology has been used by numerous civilizations throughout history, some examples of the constructs in Eorzea being so old that their origins have been forgotten outright, while some can be traced to Allag and the newer ones can commonly be traced back to Sharlayan. Scholars of Sharlayan first found ruined Allagan aetherytes in the year 598 of the Sixth Astral Era, reverse engineering it to begin producing new aetherytes. Within less than a decade each of the four isles of Old Sharlayan had an aetheryte on them, and were successfully developing teleportation techniques using them. By 902 Sharlayan had formed a contract with the Sultanate of Belah’dia to construct an aethernet (a collection of aetherytes) in their territory of Thanalan, although within roughly half a century this effort met with tragedy. Belah’dia had entered a ferocious civil war between two siblings, resulting in the split of Ul’dah and Sil’dih, and in response to Sil’dihn use of the aethernet to assault the Ul’dahn camp, the Ul’dahns destroyed a good section of the aethernet, prompting the ever war-averse Sharlayans to suspend the construction of the aethernet, delaying its completion.
The Tenkonto of the East
Although the modern aethernet of Eorzea was constructed in vast part by the scholars of Sharlayan, their equivalents in the East, commonly referred to as Tenkonto, were built by a native organization known as the Onishishu. These craftsmen are a multi-national, neutral organization devoted to a form of populist ideal, serving the people in exhange for only very modest payment, which can be tendered in currency or traded goods such as food. It is common scholarly opinion that the knowledge that birthed these constructs originated with Allag, just as the aetherytes of Eorzea did, although the Onishi have a particularly secretive culture and history so confirming this is difficult.