Welcome to the Elm.
You would never see the Elm if you were to live on one of its many reams, in the same way that one can't see their own galaxy from where they're standing. The worlds of the Elm float just off of its branches like planetary fruit, each harnessing Sap from the mighty tree to fuel both magic and life. It is said that Gods harness the most Sap in exchange for their nurturing of the Elm. Overgods rule from the sky to rain water and hope to the Elm's inhabitants, and the Undergods rule from below to enrich the Elm's soil with souls of the damned.
Or so the legends say.
The many worlds of the Elm are not easily traversed. Dangerous environments, the forces of gravity, and natural barriers prevent many realm inhabitants from ever leaving through normal means, but exceptions have been made. Whether by space faring Espelship or interplanetary portals, hundreds of empires have risen across a multitude of worlds and nearly as many have fallen. Yet their influence remains. Worlds that once hosted a single race now see exotic species and cultures changing the shape of politics, war, religion, and culture.
None are to blame for change more than the Espers. Named for their Extra-Sensory Perception, every esper is able to sense the ebb and flow of magic and raw power, the strength that fuels mythical monsters. By detecting this energy espers are able to find their own minuscule source and strengthen it to master both might and magic alike. This process is akin to finding a new muscle. Becoming an esper is a dangerous task, and many espers fall to overexertion without proper training, yet for each young esper that fails there is another who reaps the rewards.
But you know all about that. Don't you, esper?