CONTAINS SOME SERIES SPOILERS!
I'm far too lazy for a full theory, but I've always thought that, prior to Terranort losing his heart to darkness, Master Xehanort himself was the byproduct of another similar transformation. Quite literally, Another. As we know, Xehanort's name has two Xanagrams (officially coining that term) that have been officially pertained to in the Kingdom Hearts universe. We have 'No Heart' seen as the name of an extra boss donning Keyblade Armor identical to that of Xemnas and wielding Master Xehanort's Keyblade. then we have 'Another', something seen entered into Ansem the Wise's (Ansem's the Wise? No...) computer by Xemnas as a password to the hidden Chamber of Repose.
Now, beyond those two facts the rest is speculation, but that's the fun part! I speculate that Master Xehanort is (okay, was) a Nobody. 'No Heart' may have been someone who lost their heart, becoming the first Heartless. Their body, then becoming the first Nobody is somehow given a new name, likely in a similar ritual to Xemnas' names for the member of Organization XIII. 'No Heart's Nobody, takes on the moniker 'Another', describing his connection to his counterpart. Note the wording used to describe a Nobody int the first research they were discussed in.
Spoiler Show
So we have 'No Heart' and 'Another'. The latter of the two is essentially the prototype for the Master Xehanort we have all grown so fond of. After a while of experiencing his new existence, sans heart and purpose, 'Another' begins to gain his own identity and grow more self-aware. Yadda yadda yadda, he eventually sheds his purposeless shell of a name in some existential journey of self-discovery (likely including the discovery of some life-altering source of purpose - the χ-blade). In some sort of surely story-filled and epic way, the young man previously known as 'Another' finds his new heart's calling in the pursuit of this χ-blade and devotes his life to unlocking it's mysteries. He forges his new name. χehanort.
Now, how does this bring us to the events of Birth By Sleep? Well, somewhere along the line young Xehanort, in his obsession, crosses a line. Perhaps a similar thing is done to him as was done by him later to Ventus. Perhaps someone extracted his hearts darkness or otherwise locked it away inside his heart out of fear, rendering him comatose. With his heart in a state of slumber, and his master fearing it too dangerous to unseal the darkness in his heart, Xehanort is essentially exiled to Destiny Islands, and there remains in slumber... Until the heart of a boy reaches out and mends Xehanort's heart. A resident of Radiant Garden. Braig (Xehanort's future accomplice who might be the one who discovers the Chamber of Repose in the basement laboratories of Radiant Garden's castle and brings it to Xehanort's attention).
This brings us to a young Xehanort standing on the shore, where he receives a mysterious visit from a man in a brown robe.
So, recap and other stuff...
- A man loses his heart to darkness. Heartless = No Heart. Nobody = Another.
- Another grows a heart, becomes obsessed with χ-blade. Becomes Xehanort.
- Xehanort's obsession grows darkness in his heart. His darkness is sealed away, breaking his heart, rendering him comatose, and damaging his memory.
- Braig's heart mends Xehanort's.
- Perhaps -and quite likely- the Chamber of Waking can return a sleeping heart to it's body for awakening, in collaboration with the Chamber of Repose. Maybe after possessing Terra's body, Xehanort was able to access certain memories inside Eraqus' heart (as it resides in Terra too) and discover information of a second Chamber, residing in the former Land of Departure (or he already knew of it somewhat, since he had the same Master as Eraqus did). And after discovering hat Aqua holds the key to that place, he tries to use her armor to find her. Maybe Xehanort is trying to find a way to rejoin himself, 'Another', with 'No Heart'.
Oh, and Guardian would be Xehanort's sealed darkness, released after Xehanort stabbed himself. Kind forgot what miy point was in writing this... Haha.
Sounds a bit fanfictiony to me. We know that the 'mysterious robed figure' that visited YX was Ansem as he admits as such.
And so far the No Heart armor fight isn't a canon thing just like Eraqus' Armor isn't. The fact that Xemnas had the armor in KH2 shows its' likely the armor MX said he abandoned use of in his BBS reports.
And we know MX couldn't have formed the first heartless/nobody because:
The heartless are far older than MX because they originate from darkness which itself predates the current universe.
As for YX pulling a Ventus, well we know that can't be the case:
Xehanort's Report 8 said:
Although Xehanort mentions sneaking away in his youth, it's not till the flashback scene of when MX gives Eraqus his scar that he truly leaves for good.
So that pretty much cuts the idea YX was sealed because his reports point out he stayed at LoD with occasional travel before finally leaving.
As for MX knowing of the chamber in LoD well it's safe to assume Xemnas gained that information due to Eraqus' memories but Xehanort shouldn't have had that knowledge prior. (unless he was ease dropping)
The LoD to CO thing is a "trick" only the "True Successors" know. Only one true successor exists at a time among the masters, currently that is Aqua.
Meaning even though they had the same master, MX wouldn't have been told such info because Eraqus was chosen as that true successor by their master as Eraqus chose Aqua as his among his 3 pupils.
We don't exactly know what "true successors" know that normal masters don't but the fact there is a distinction must mean they hold knowledge not meant for the other wielders to fulfill whatever role it is they play.
As for this "Another" that took up the name Xehanort, that can't be possible because we have Young Xehanort in DDD that comes from a time period before Xehanort left the islands.
His name was the same then as it is now.
I will say though, despite the holes, the idea that Xehanort may have lost his heart to that initial acceptance of darkness stated here:
[QUOTEXehanort's Report 2 (BBS)]
Our Master instructed us to don armor while traveling between worlds, so that we might shield ourselves from the darkness. But there, in the Lanes Between, I could feel the force of it - the power - and from then on, I forwent my armor's "protection." I had been told the darkness would devour me, but what terrors could it possibly hold, so long as I found the strength to control it? [/QUOTE]
I could see the possibility of it. Xehanort in various forms says he "embraced" the darkness but how that would be different from yielding to it doesn't make much sense.
It could be possible that in those early days of training YX inadvertently lost his heart to the darkness reforming as a nobody.
Though this itself has at least two holes.
1) The keyblade, can't wield a keyblade without a heart. The only exception to this rule is Roxas who has been confirmed to be merely borrowing Sora's & Ven's which itself it only happening because Sora wasn't a heartless long.
Had Xehanort became a nobody he wouldn't have been able to continue his training as a wielder. Granted he could've eventually formed a new heart but that takes time.
2) Know how. From what we can gather at current, even though MX knew of the heartless, it wasn't until his time as "Ansem/Apprentice" that he learned what forms them. If this is true then it leaves the question why he'd only figure that out as an apprentice when he already became a nobody prior.
It's possible for the dark halves I suppose but it being the actual thing would be impossible given the merger of the three is far from balanced.
