Board Thread:Manga/@comment-26495049-20161117013314/@comment-27441457-20161117033404

Well, I'm currently going by the assumption that the Eldians are the "majority race" of the walls, meaning that only Eldians are susceptible to the Coordinate and Titan powers. Since Levi and Mikasa's ancestry must have intermingled with Eldian blood during their time within the walls (Levi especially, due to his unknown father), and since it's implied that half-Eldians can still become Titans (1,700 years of eugenics), it's still very likely that Levi and Mikasa could become Titans. The immunity to the Coordinate due to their Ackerman (+Asian in Mikasa's case) ancestry must be something that overrules the Coordinate's influence over Eldians.