Editorial: Who Are Xehanort's Thirteen Seekers?
Ever since Dream Drop Distance came out it's been a question on every Kingdom Hearts fan's agenda - not as pressing a question as 'what's going on with time travel again?' or 'how much has Nomura lost his grip on any semblance of good storytelling?', but a question nevertheless.
A lot of people have thrown their views in. Now I'll throw in mine.
The ones we know:
So far, we know of six out of the thirteen. Master Xehanort, the old man himself, takes top position as Number One in the Organisation, while Xemnas and Ansem (Seeker of Darkness) take up position as two and three respectively. Xigbar is number four, and Saix is number seven. Finally, Young Xehanort, the teenage version of Master Xehanort, is number twelve.
That leaves seven to figure out: Numbers five, six, eight through eleven, and finally thirteen, the spot originally reserved for Riku or Sora (and variants).
Number V: Eraqus.
Eraqus is one that I haven't seen turning up on a lot of lists, and that's a little surprising. Xehanort, after all, holds Eraqus in very high regard: They're students of the same master, Xehanort practically considers Eraqus a brother, and he fears Eraqus enough to refuse to take him on in direct combat, instead having Terra defeat him before striking the finishing blow.
Eraqus 'died', obviously, except he didn't, did he. We know that Eraqus' weakened heart is inside Terra, and while his body vanished into light, so did Xehanort's when he swapped bodies, yet his body was apparently well enough for it to make a reappearance as 'the most future version of [Xehanort].'
That means that in all likelihood, Eraqus' body vanished only to reappear as a Nobody - and while Xehanort might not have been inclined to recruit him into the first Organisation, Eraqus' Nobody would make a fine vessel for Xehanort's heart, especially when it comes to filling the gap left by Sora foiling his plans in Kingdom Hearts II.
Number VI: Terranort.
This one is practically a given, and pretty much confirmed. While we never see Terranort, Xehanort says outright that two of Mickey's seven belong to him now, referring to Sora and one other (out of a list of Mickey, Riku, Sora, Aqua, Ventus and Terra). That one other is almost certainly Terra, arguably the original Xehanort clone of the bunch.
From a gameplay standpoint, Terranort functions differently to any of the Xehanorts we know as well. He's slower, more powerful, specialises more in fire and earth magic whereas Master Xehanort prefers ice, Xemnas prefers lightning, et cetera. He's almost guaranteed to be one of the remaining seven.
Number VIII: Larxene.
This is probably the most difficult one for me to justify, but golly, do I want it to be true. Larxene's one of my favourite Organisation members, after all.
Larxene is just - she's really cool, okay? She's a lightning ninja who can produce a copy of herself and who has sadistic tendencies.
She's also actually not a terrible candidate. We know that Xaldin, Vexen, Zexion, Lexaeus and Axel are off the list, since they all reformed in Radiant Garden. We know that Roxas is off the list. That leaves Demyx, Luxord, Marluxia and Larxene. Two of those are further along on this list, and Demyx, being the first Organisation's standard issue unmotivated waste of space, seems very unlikely.
More of a 'I want this' than 'I think this is likely', but there you go.
Number IX: Riku Replica.
Again, very nearly confirmed. In Dream Drop Distance, Riku sees a black-coated figure trying to steal Pinocchio away, and when the figure draws back its hood, it's a younger version of him. Some people have dismissed that as part of the dream, but at no point does Riku ever experience delusions or see figures from the past while in the dream world, unless they're actually there. Also, the Riku there is wearing a black coat, which Riku never wore at that age.
Riku Replica also makes sense for Xehanort's plans - we know he wanted Number XIII to be a keyblade wielder, quite possibly the wielder of the Kingdom Key. As Xigbar pointed out, Riku was the one they originally meant to fill that slot, and it was only when he was unsuitable that they moved down to Sora.
But wouldn't a sensible intervening step in that plan be to recruit Riku's Replica? Xehanort might well believe that Riku Replica could wield a keyblade, only to be proven wrong, since this is one area that we know he's not an expert in - he needed Vexen to run his Replica Program for him, and when Vexen died, the program practically had to be shut down.
Number X: Luxord.
Luxord is Tetsuya Nomura's favourite Organisation member, and he's pretty well-beloved by fans. He's also the Nobody of Time, a fitting addition to a group that can only assemble its members via the rigourous abuse of time travel, and was a trusted enough Organisation member to act as one of Xemnas' guards, being one of three Nobodies you fight in The World That Never Was. The other two, Saix and Xigbar, are both part of the Thirteen Seekers.
It's also worth noting that Chair #10's resident keeps his hood up, meaning we never see his identity. That's not necessarily compelling evidence - Xemnas and Xigbar have both changed chairs, while Saix is the only one we know to still be sitting in the same place - but it's a worthwhile consideration.
Number XI: Marluxia.
Marluxia is often brought up and then dismissed by people, since as a traitor, he would fall under the 'weakness of trust' exclusion clause. But Saix was also a traitor, remember, at least at one point - he and Axel were plotting together.
If Marluxia isn't included, then he would be the only main villain not to be a part of the line-up. Ansem (Seeker of Darkness) was the main villain of the first game, Xemnas the second, Master Xehanort and Terranort for Birth by Sleep, Young Xehanort for Dream Drop Distance, and Sora for re:coded, 358/2 Days, and Dream Drop Distance, in various forms and personas - Data-Roxas, Xion, Armoured Ventus Nightmare, so on.
(Wow, Sora's been a boss monster in almost as many games as he's been the protagonist. At least two games have him as both.)
Not to mention that, like Luxord, Marluxia is very popular with fans, and like Luxord, the resident of his old seat has been left unrevealed.
Number XIII: Sora.
Sora is, technically, one we know, but as Xehanort failed in his initial attempt to implant a heart shard into him, he might be off the list.
I don't think he is, though. Xehanort doesn't seem shocked or particularly put out when his attempt fails: He doesn't act like the rug has been swept out from under him so much as he acts like someone who just has to put in a tiny amount of extra legwork to get what he wants. Sora, I would think, is still very much on his list.
Not to mention that if the games haven't been building up to Sora eventually falling to darkness, however temporarily, then I don't know what they have been building to. Sora's become a Heartless and a Nobody, and had the effects of that linger in his heart enough to make AntiForm a thing. He spent several years of his youth linked to Vanitas, enough so that Vanitas looks like him, and he's reintegrated Xion into himself - Xion, who was neurotic and trying to consume Roxas when we last saw her. He may even have ended up absorbing Vanitas into himself when Ventus took shelter in him.
Add to that that Dream Drop Distance had his heart be shattered, and had him become a Nightmare, and Sora seems to be careening down the road to darkness. He'd make the perfect candidate for Xehanort now, obliging Kairi and Riku to fight him to snap him out of it.