With the confirmation of the new Organization and it's significance is definitely sprouting a bit of speculation on who exactly who is occupying the six other seats and who will fill the final one completing the 13 darkness. Old faces will no doubt return in more sinister matters along with new faces but as of this moment here is a list of old faces I wouldn't find surprising to being a member.
-Dilan-
Xaldin was loyal to the cause of acquiring Kingdom Hearts in the same matter and authority as Saix, despite the ranks. He stands by Xemnas in the interrogation of Axel, even threatening him in his displeasure of Axel's obvious grief on the order of exterminating Roxas. Xaldin again demonstrated a harsh tone over the ordeal of mimicking emotions among other members.
For a man who was merely a sentry before Org 13, he is very manipulative in controlling the darkness in hearts. Example would be his hypnosis on the Beast, utterly consuming him in his on Anger and despair- the very tactic Master Xehanort himself pulled when he tricked Terra in accepting the darkness.
Dilan was surprisingly absent after he awaken along with the others in Ansem's study. This may suggest a probability he has returned to Org 13. Another potential but subtle hint of his own Xehanorfication is that Xaldin's ears are pointy like Isa's and Braig's whereas his original state in BBS does not.
Advantage: Immensely powerful, ruthless, and loyal. Capable of control Dragoon Nobodies.
-Even-
Even never shy away on potential discoveries regarding the heart and his experiments proves as much. His loyalty may come from fear of Xemnas himself but genuinely speaking his experiments merits were always for the cause for Org 13 - he is responsible for the creation of Riku-Replica and Xion after all. A chance to return to Organization 13 would be a chance to continue his work with no quarrel of morality. There really isn't any physical or mental evidence of his own Xehanorfication but prime curiosity of the hearts compares greatly with Xehanort's.
Advantage: Experimentation of hearts than can lead to clones and other mechanisms.
-Riku (KH1)-
At the time before he sacrifice his heart to Ansem, he thought he was at the peek of his control over the darkness but was proven wrong by his defeat from Sora and disqualification of possessing the keyblade. He threw away his home, his friends, his own self conscious for the sake of power and became desperate to accepting any sources even fully opening his heart to darkness.
At the time he was suppose of be approached by Ansem, he would be approach by YMX with an offer to join the new organization which Riku would accept graciously. A prime evidence of this possibility was during Riku's trip inside Monstro he meets his KH1 self briefly with an Org coat before he departs.
Advantage: Control over the darkness and the heartless. Easily manipulated. An emotional battle trial for the real Riku.
-Vanitas-
Vanitas is the incarnation of Ven's darkness. What more can you say about his qualification of being one of the "13 darkness?" He IS darkness itself. A psychopath capable of producing hordes of unverse by his flagellant emotions alone. A evidence of his potential return is the very moment where he appears out of no where behind Young Xehanort about "hearts that don't belong to you."
Advantage: Keyblade Weider capable of summoning the Unverse.
-Terranort-
The man that started the heartless chaos. Despite all his memories being in oblivion his fascination of the heart and darkness leads him to the world's ultimate demise and pathway to his goals. More than likely the point in time where he receives the memory of being a keyblade wielder will be a proper point in recruiting him to fold.
Advantage: Keyblade Master and controller of Darkness, potentially the Guardian.
The other 6 could be the nobodies of Dilan, Luxord, Axel, Demyx, and so forth. Eventually we didn't know Saix was there because he looked indentical to the other Xeohanorts and we couldn't tell by the physhique of who was who. But when he went after Lea we saw a weapon in his hand and his face. Xenmas stated that they have two hearts or could so maybe he made those nobodies hearts out of the organization members that were defeated in KH 2. He already can use Xaldin, Saix, Axel, Demyx, Luxord, power weapon in that game and it would explain how he can still use them.
This would explain why he didn't seem that much worried about Lea interferring. Xeohanort didn't as much either. Briag though seem disturbed. Lea also got in the way of the power to save Sora by Xeohanort. This must mean something. Perhaps got affected.
Nobodies have the ablities to create clones so perhaps they can make manifestations of themselves and others as well. YMX, Xenmas, and Briag seem to make illusions or create dreams. So they could create more members with the ones that were killed off.
Xeohanort army we do know.
Xeohanort
Xenmas
Xeohanort SOD
Young Xeohanart
Xigbar
Saix
This one makes more sense with the others
Xaldin
Luxord
Axel
Demyx
Ventus
Terra Xeohanort
Can' think of other one except Replku or even Vexen. For all we know he never woke up or was still unstable.
One of the Xeohanorts mentions Xeohanorts of the past and the other organization members are from the past.
Luxord, Demyx and Axel have control over their own lesser nobodies as well besides Saix and Xaldin and Xenmas. Roxas did as well, but he is a different story. They were good manipulators and deceitful.
Another possiblity
Xaldin
Luxord
Demyx
Axel
Marluxia
Larxene
Then again Saix knew that Marluxia, and Larxene were traitors in CO so I doubt it would be them. They wouldnt want to come back to the organization, but I am not counting them out. Larxene didn't want a heart, Marluxia I think didn't either. They wanted their freedom, but also power.
Yes I know that Axel and Lea are different, but it still points to that Axel is still around somewhere. Nobodies having two hearts is another example of it. Plus we don't know if Lea had powers before his nobody Axel came into the picture. We do know that Lea kept his powers when he woke up. Axel also knows how to kill and is manipulative and deceiful as well. If you reborn a nobody without any connections to certain people then you have Axel from COM.
Saix could bait Lea since Roxas isn't in the picture anymore and plus Lea would want to save Isa. It never explained Axel's pain so this could be it to save Saix/Isa. Also wasn't Lea going to find the other members?
Demyx was the only nobody who worried that Axel was missing from the organization and never pried him as a traitor like ther others. He could be a lost sheep in so many ways. He hates fighting, but he does know how to if he is forced. He also hates Saix, but never Axel who is in fact fire while Demyx is water. I can see him interacting with Axel/Lea and also Axel defended him in Days so that must mean they have history together. When Axel was Lea he mentions he had friends not friend. So Isa wasn't his only friend. Perhaps Xigbar kept them apart. Axel and Demyx could be rivals really easily.
Luxord is loyal to the organization so I am sure he will be back. He also has this time warp thing as well. Not to mention Normua's favorite organization member.
It is more logical with these characters since it would be stupid for Noruma to create more new characters when you have others that were already in the mix.
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