Board Thread:Show-Related Questions/@comment-24670104-20150405210036/@comment-26247132-20150411014615

TheOmegaWerewolf wrote: Lexa did say each Commander is chosen by reincarnation. That means there were people that led the Woods Clan before she did and their title was Commander. I think Lexa just kept the title Commander when she became leader of all the Clans. Here is the actual dialogue from Survival of the Fittest:

Clarke: You want to know why I saved you? Because I need you. God forbid one of your generals becomes commander. You may be heartless, Lexa, but at least you're smart. Lexa: Don't worry. My spirit will choose much more wisely than that. Clarke: Your spirit? Lexa: When I die, my spirit will find the next commander. Clarke: Reincarnation. That's how you became commander. How are your leaders chosen?

Then they get interrupted by the gorilla and it's not brought up again.

So, the only thing Lexa, a grounder, confirmed was that her spirit will choose the next Commander. Clarke, a sky person, is the one who inferred that Lexa became Commander through reincarnation, but she still speculated on how the grounder leaders were chosen. Either way, none of it was ever confirmed by Lexa.