Jon (553-567)

 The chapter begins by describing the corpses of two men (Ben Starks men, to be exact). The corpses were dead white, with bright blue eyes and black charred hands. They found the dead men outside of the wall while looking for Ben Stark.  Jon and his companions of Black Brothers made the mistake  of taking the bodies back to the wall for further examination. Jon awoke the next morning to find the dead corpse alive! The zombie had killed men already, but Jon being the hero that he is, ran to make sure Lord Mormont was safe. In the battle between Jon and the zombie, Jon won by using FIRE. Apparently zombies are allergic to fire. Throw in some bad news about Jon's father and a quarrel between Jon and Ser Alliser  Thorne and that pretty much sums up the chapter. 

 This chapter changes things quite a bit... For instance zombies are now an imminent threat to the wall. It seems like the zombies were meant to be found and that there are probably more. Jon lands himself in trouble after attacking Ser Alliser, and we see Jon becoming troubled that he isn't able to help his true family. We also see a close relationship forming between Jon and Lord Mormont. 

 I think that zombies will definitely become more dangerous and that it will cause more problems for the kingdom (as if there's not enough already!).