The world of Game of Thrones is full to the brim with shady characters. There are evil queens and scheming courtiers, mountain-sized baby butchers and fire-breathing dragons and straight up creeps like Ramsay Bolton. But if we absolutely had to name the single biggest threat facing Westeros and the Seven Kingdoms, we would probably settle on one enemy in particular: the White Walkers. These mysterious ice folk are advancing on the Wall with their army of the dead. They've taken down multiple brothers of the Night's Watch, and (in the TV show) at least one dragon. They don't exactly seem like good news.
But, in defense of the Others and their whole creepy deal... we don't know that they're actually bad news, either. We still don't know what they're after at all, or why they're heading south. On the HBO show, it seems like they're bent on world domination or some such nonsense, but in A Song of Ice and Fire, things are not so clear cut.
Here's what we do know:
A lot of folks, including the Red Priestess Melisandre, seem to think that the Others are evil, point blank. Mel believes that they are servants of the Great Other, some kind of cold, clammy devil figure. But George R.R. Martin has said numerous times that he's not especially interested in conflicts of good vs. evil.
As Martin puts it: "The battle between Good and Evil is a theme of much of fantasy. But I think the battle between Good and Evil is fought largely within the individual human heart, by the decisions that we make."
So it's unlikely that the White Walkers are out to exterminate mankind just for kicks.
Let's start with this: the White Walkers (also called the Others) are not zombies. They're not undead humans, they're strange, beautiful, living ice creatures. They can raise the dead with their magic, though, and possibly control them. Legend says that the Others brought about a super gross and long winter, many generations ago, and that they were defeated in the Battle for the Dawn. It seems like the Wall was erected to defend the lands of man from the Others — apparently, the Wall is made of super special magic ice that keeps the Others out. Even Friendly Ice Zombie Coldhands is unable to pass through it.
The HBO show has revealed that the White Walkers were created by the Children of the Forest in order to defend themselves from mankind. So it follows that, in the show at least, the White Walkers might be trying to carry out some version of their original purpose, and end the reign of man. That's certainly possible for the Others in the books... but I'm guessing that their end game isn't as clear as all that.
After all, the Others seem to have some kind of symbiotic relationship with humans. They like taking Craster's baby boys, at least, possibly to turn into lil' baby Walkers themselves. And there is a legend of the Night's King, an ancient Lord Commander of the Night's Watch who got hitched to a White Walker lady. According to some stories, they even had kids.
(...I'm not saying that the Starks are the descendants of those human-Other kids... but I'm also not not saying it.)
So, it's at least possible that the Others and the humans were once on speaking terms. I mean, the Wall is made up of some pretty freaky ice magic, and the Others seem like the go-to source for all weird ice sculptures in Westeros. Perhaps they made the Wall as part of a treaty, a pact with mankind to split up the North. Perhaps they're only heading south now because humans have (unintentionally) broken this long forgotten pact.
Are they upset that the Wildlings are running around up North, since they don't want humans on *their* side of the Wall? Are they pissed off that the Starks have been kicked out of Winterfell? Are they not getting nearly as many babies as they used to?
Or are they scared of dragons?
It seems like the White Walkers waking up and getting down to business has coincided pretty neatly with Dany hatching her baby dragons. The Others might be heading South to get rid of these pesky Targaryens and their fire magic. Or maybe they need the dragons for something. Maybe the summer was way, way too long for them, and they need to act to bring winter back.
Maybe, just maybe, whatever thing the Others are searching for is the key to why the seasons on Planet Westeros are so darn screwy.
And if you want my personal crackpot theory, I'm betting that "thing" is our buddy Jon.
At least, if our baby Jon Snow is truly a Stark-Targaryen, half ice and half fire, it's possible that the White Walkers have some very strong feelings about that, and that they're heading south to give him a stern talking to.
Whatever they want, it seems likely that the Others are marching because of some ancient pact that was broken, and not just because they want to ruin everyone's day. It seems almost certain that they're not random agents of evil, but a group of intelligent beings who are following their own set of rules.
Let's just hope they figure out how to ask for what they want with words, instead of with an incalculable army of the undead.