My theory is that Birth by sleep is about an eclipse. Someone posted a thread showing symbols from terras attacks in fm+. Duroing a lunar eclipse the sun or light is bloked out and during a solar eclipse the moon or darkness is blocked out. If you watch the secret trailor hd you can see That mx's keyblade is the ultima weapon keyblade from kh2 or the lunar keyblade. It also shows him using it for what looks like kingdom hearts. What if VATs master wields the solar keyblade. I think that keyblade wielders had split between light and darkness. Twilight chose sides while dawn picked the side opposing their styles of light or dark. The problem was that the dark decided to use the lunar keyblade. They also collected the PoH to destroy light. Though there are beings of pure darkness like PoH. They are called demons of darkness and amongst them is xehanort. He is projecting himself through the DS as we saw with xehanort and riku. That is how xehanorts heartless retained his form. Nobodies of people with demons of darkness have one non existant like roxas's keyblades. Marluxia has a DoD in re:com so does xemnas and xehanort. Riku has one during fm+ which is why DiZ called him a DoD. Also like at the re:com scene where xehanort talks about possessing riku. In the secret video terras eyes go gold like others have when using darkness because the eclipse prevented the use of light. With gone terra fought using darkness until he called forth enough for mx to possess and project himself from him. Chasers are the keyblade wielders of a path or eclipse they decoare their keyblades with keychains. The other keyblades are scattered across the universe. The new enemies are souls created when a body is destroyed releasing the heart to KH. Also the cave of sleep is in radiant gardens (light). Castle oblivion holds (cave of awakening). The world that never was doesn't exist while the cave of ??? Is in a castle from the realm of darkness. Maybe ven died but lived on through sora because of soras memories and erase me my friend was a thought like when xehanort and riku talked. Maybe Sora Riku and Kairi have armors too that they will use later because the are just the best right now because they are the only wielders and are weaker than VAT. Terra has been resurected after kh1 ansem and xemnas were destroyed. When connected to egyptian mythology you'd know mx looks like osiris annubis or terras father. Also notice that the eye of ra in soul eater way to dawn and a spear in kh1 was a tool used by annubis and osiris and it is also found on the walls of radiant garden in kh1. I still don't know atw's role in this though he most likely has one.
