Hmm... A Flood (of light or darkness) on one of the splinter shards renders it unable to be joined to the main shard, our shard. What happens when a Flood happens on the Main Shard though? Are the other shards able to still join with it? Can they only join with it if a similar Flood has happened on them?

What if a Flood is what needs to happen to Hydalyen to kickstart the process of Zodiark breaking free of the moon?