What if, the moon is actually the original world, and the one we are now was the one created by Zodiark when he sacrificed the first half of the population. Which is why the moon is now a dried up husk (mostly) since Zodiark has been sealed away and he's the will of that planet, with Hydalyn being the will of our planet. And the reason why our planet was sundered when Hydalyn attacked Zodiark was because Zodiark created it.