Floating islands and countries exist among this rewritten Mobius.
Since the Sonic universe is set much more in the future with my worldbuilding of generational advancements, it means, that the sky islands were at a quite primitive stage.
Said sky islands were mostly inhabited by birds and some nocturnal creatures, whom at first were bird-hybrids, turning into a mutated bat-species for example. Only hybrids are able to live on these islands, or else they have to eventually get back to the surface and breathe normal oxygen.
These skyislands, originate from three locations; The alps, a few from Siberia, North- and south-poles, aswell as a few from Mayan Mexico.
It is unknown to the folk, on why the islands are able to float, though they also are unaware, that deep in those islands, are certain crystals of pure chaotic power, hidden below the land. Forged by angels, though deemed too destructive, they were called "Chaos Emeralds". What was intended to be used against the century-long battles versus demons, now unintentionally has been found by mobians. While the angels are blissfully unaware, they do know, that floating islands exist over their sky-realm. So long they do not cause trouble, they do not mind them either.
Angels in a sense, unintentionally protect the sky-islands from any evil, due to them inhabiting the clouds beneath them.
Those who live on these islands, aren't even aware, that they live right above a plane of deities and angels, due to them being spirits, something that normal mobians cannot even see.