The Night's King can create other white walkers; remember how he turned the Craster's baby into a white walker just by pointing it in the face? Craster would sacrifice one of the incest babies he had with his daughters so that they wouldn't get overran (if I'm remembering correctly).I just realized something. I noticed in Bran's vision there were four Others on horseback. Didn't Jon kill one of them? So, is Bran's story arch lagging behind Jon's? But Meera killed one of the Others too, but Jon still saw four at Hardhome and not three. Am I missing something?