My current crack theory is that we'll end up with one Archon each paired off against a corresponding Ascian (and either Minfillia or the WoL paired off with the 13th, Eldibus).
2.5 spoilers:
Considering Moenbryda sacrificed herself to eliminate Nabriales, that leaves eleven (plus one) matchups to go.
What that means going forward is anyone's guess, but something tells me that uniting all twelve in some special attack against Zodiark is an all-too-plausible direction for the ongoing myth arc.
Springing off of a question from the thread Moose linked, what is up with those tats? They don't simply designate Circle of Knowing members, or Ramnbroes would have them, and they can't really just be a general marker for Sharlayan scholars, or Y'mhitra would have them, too. The eye insignia is especially interesting, because (from what we've seen) it only started being worn after Louisoix's sacrifice at Cateneau. (Or do the echo scenes from the 2.0 starter quests retcon that?) But it can't be exclusive to the disciples of Louisoix, unless there's a hell of a lot G'raha kept quiet about. I also don't think it designates Students of Baldesion, because you'd think a Student of Baldesion would notice that first when two imposters walked up to him.