Eaden is a Collection of parallel universes, While travel between these universes is extremely difficult, knowledge of their existence is fairly commonplace.
As we all know, Eaden is a World of Worlds, Each World is a Cluster of floating Islands in a vast empty void, however Eaden is not the only realm. The Great Arcane Scholar Leprix Apkal hypothesized that with the rebirth of magic other realms began to surface, small tears in the bubbles that separated them in the greater cosmos allowed aspects of these realms to Filter in to Eaden, Filling the Void with Air, causing endless Springs of water, Illuminating the Central Suns, Ect. However I think there is much more to it than that.
I believe Eaden, our world is the anchor that all others connect. Acting as a focal point for each other realm it is what binds them all, originally Leprix believed that the Realms were just parallel worlds to Eaden, copies if you will, that each had a different history and thus a different outcome. However there are a few flaws to this theory. First it has been well documented by the few who have traveled to the other realms, that time does not travel the same as it does on Eaden, with some traveling slower, while others travel significantly faster. This fact by it self should disprove Leprix's theory. Second, Arch Mage Yeven Von Kel, Reported that magic in some of the realms doesn't work as it would in Eaden, causing seemingly random effects instead of what the caster intended. He goes on to claim that in some cases casters may experience magical backlash that can be fatal if they are not acutely aware of the new realms magical variants. Third, Artificer Henry L'etre Reports that some mechanical instruments fail to act according to scientific norms, going on to sight numerous reports of Airships unable to work, Anti gravity crystals becoming inert, and many more. Effectively preventing us from completely exploring these realms to see if they have any topographical similarity's to Eaden. All of this points to these Realms as unique and completely separated Worlds that have somehow become linked to ours though these breaches or tears in their separative bubbles. I Propose that if we could travel safely though the Void, we could Reach these other worlds, Thus making a stable trade route, instead of relying on Unsafe magical spells, and unreliable random rips in Eaden's Bubble that take a few unprepared Travelers to a random Realm.
The known Realms are as follows;
The Void
The Elemental Fringe
Heaven
Hell
Wilds
The Realms of Legend (Realms found throughout stories, myths, and crazed Breachers accounts
Rozoncia
Ur
The Oasis