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.
-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.