Klaus did some shit and due to the experiment split a world in two: Alrest and Bionios/Mechonis World. I ASSUME that with Klaus being finally dealt with, both worlds were pulling back to one another which would have resulted in mass destruction of life of both planets. Melia+Nia+Crew created the Origin system to house digital data of everyone's souls/concsiousness. However, due to the desire for survival and safety of their current lives, their wills manifested to create Moebius Z/X/Y as some sort of defense mechanism. Z then hijacked the whole process and using the power of the Origin system, created his new world and froze time (The Endless Now). Then used clone soldiers to perpetuate the new world.. yada yada. When the 3 true moebius were destroyed, the worlds reverted back to the point prior to Z's hijack when the planets were due to merge together (the original reason for the Origin system). Because of the time rubberbanding, no one will have knowledge of the world Z and Moebius created because it literally will have never happened. Time-travel bullshit. And that's where we're at. I assume the "big" expansion will either be post-game with Noah and Mia crews finding each other post-world merge OR the founding of the City and N/M's origins as the original Ouroborous. I think the former is more likely seeing as like two expacs are new classes and it feels weird to completely ignore that. But who knows.