EVERYONE MUST READ THE FOLLOWING AS I SWEAR ON Kingdom Hearts THAT IT IS AT LEAST A PLAUSIBLE THEORY

 

Nomura said that KH3D would explain the mysteries of the series and this is the most obvious way of using the new enemies to do so.

After the Keyblade War all participants were trapped in the Dream Realm and eventually they lost their physical form in a similar way people lose their form after being exposed to the darkness for too long. Unknown could therefore be a participant in the Keyblade wars who somehow surived with his humanity (or human form) intact (in a similar way MX kept his human form), and Dream Eaters are the participants from the Keyblade War who have lost their humanity. The Spirits are the participants of light, and the Nightmares are the participants of darkness.

 

Known "facts" about Unknown

- Nomura said that wherever he goes people of the darkness show up

- He can manipulate time and the Dream Worlds are similar to Merlin's gate, in that time has no meaning (this would be how he time travels through some unknown mechanic of the DW)

- Malificent hints at enemies of light and KH is known for its ideas about unity of light/darkness in people, not about darkness being bad or light good, so this unity could explain how MX is revived as a being of complete light world screw up the worlds equilibrium.

 

I am not sure about everything, but I see this as the most plausable theory because the light is the most obvious new enemy. Add your own thoughts and completely destroy my theory if you want but it seems solid.

very nice theory but i remember reading that dream eaters are the form darkness takes in the sleeping worlds as Heartless and Nobodies cannot enter. and if i also remember that this was also said by yen sid. and the unknown you could be right but the unknown acts way to much like xehanort and he just looks so much like he while mx was a kid the unknown does a lot of things like xehanort like talking cryptically and useing his hands a lot while talking. so thats all i got to say but i do like your theory though

Yes I know that NIGHTMARES are the form darkness takes in the Dream World but explain Spirits and Nightmares; only my theory can explain the different types. Spirits= Good Participants of Keyblade Wars. Nightmares= Dark Participants of KW's. What happened to all the people after the Keyblade Wars? We know that after worlds are destroyed (as what happend to the KeybladeWars world) they either go into the dark realm or the dream realm. The original destruction caused the Dream World to be created and Unknown was the only Dream Eater to retain his human form which explains why he is so powerful in this realm and in general.

Okay, so I watched the 10 minute video and it appears that Young Master Xehanort IS Unknown. I had seen Young Master Xehanort before but did not realise that he and Unknown were the same character. This revelation has disappointed me, as the idea of kh3d explaining the Keyblade Wars excited me but obviously it is to remain a mystery forever. Introducing a new character was the only way for Nomura to do this but obviously he does not care about explaining the KH backstory and at the end of KH3 he will simply say after Xehanort is defeated "Oh, here is a new bad guy who was never referenced before". Sad face.

Okay, so I watched the 10 minute video and it appears that Young Master Xehanort IS Unknown. I had seen Young Master Xehanort before but did not realise that he and Unknown were the same character. This revelation has disappointed me, as the idea of kh3d explaining the Keyblade Wars excited me but obviously it is to remain a mystery forever. Introducing a new character was the only way for Nomura to do this but obviously he does not care about explaining the KH backstory and at the end of KH3 he will simply say after Xehanort is defeated "Oh, here is a new bad guy who was never referenced before". Sad face.

 

That's a pretty big assumption about KH3 to make. Don't let YMX=Unknown get you down because it was never confirmed that it was Young Master Xehanort. You could be right about him being from the Keyblade War because nobody confirmed he was YMX. That's just something the fans call him because of how he looks.