I am not a fan of parallel dimension/world, but that could very well be a possibility.

Based on what she and the Gerun Chronicles have said: she banished Zodiark into the moon and split "the sea" (aether ... The Source?) into 13 or 14 shards. I am guessing The Source could probably pre-date Hydaelyn-Zodiark and might have been the one to create them, such power might've been what Zodiark was after prior to the split?

But what is the Source? Source of all life, aether ... etc? Due to the Asciens collecting "keys" and their goal of forging a final key + them being robed figure of darkness I am getting a Kingdom Hearts vibe.

That and this thing in Chrysalis looks alot like a gate/door


They are split and the Asciens are actively trying to Rejoin the worlds/ dimensions. In fact, the Sharlayan scholars + students of Baldesions who disappeared were all researching "Dimensional Compression" aka Rejoining according to ancient texts.

I wonder if this is similar to FF8's Time Compression?