This is interesting. It definitely looks like something is up there.
Yeah my guess is that Elysium is probably some floating city on top of that tree, possibly where the Blades originated from.
Also this screenshot in particular makes me think the game will have a similar setting to XC where people live on top of these massive living beasts instead of 2 mechs.
That reindeer looking creature looks way to big to fight especially since it doesn't look like mechs will be returning.