Board Thread:General Discussion/@comment-25176701-20160205030219/@comment-26500342-20160205224440

Perhaps, the Nightbloods are linked to the commanders because how Lexa said "he's better than I was when I was his age" makes me believe she went through the same process as Aden is right now. Perhaps once you are part of the Nightbloods then you are eligible to be the next commander. Even though we can assume that if Lexa were to die, her spirit would find someone to take her place, what if they already know that it will  "choose" one of the Nightbloods? That would make it a lot easier to find who is the true commander. I wouldn't be surprised if it was somehow linked with A.L.I.E. and the City of Light either. Apparently there was an infinity sign somewhere in Polis (A.L.I.E.'s symbol). Maybe all Nightbloods are chipped or something, so A.L.I.E. can access them through the City of Light, therefore choosing the commander.

I just have a feeling that A.L.I.E. has something to do with this so-called "reincarnation". But this is probably still farfetched.