Fireballs will be hurled to fight back the SPOILERS but there may be too many of them. Until you are caught up to the very latest episode of Game of Thrones and probably the books, hold the door!
Now we know that the Children of the Forest created the White Walkers and it proved to be a pretty horrible thing to do. The Children are seeking redemption as well as reaching out to Man, their former enemy, to defeat the weapon they created to defeat the First Men. Yep, that’s how it goes with Game of Thrones/A Song of Ice and Fire.
We learn that Leaf created the first White Walker by sacrificing a man with an enchanted dragon glass knife. His eyes turned frosty blue and everyone at home jumped up off of their couches. What have you done, Leaf?! She and the rest of the Children of the Forest have been paying for this mistake for centuries.
These Children of the Forest White Walkers were a strike in a continual war with the men who chopped down their sacred weirwood trees. The First Men also slaughtered many of the already small population of original inhabitants of Westeros. Yes, the Children were here first. And Man was being all Manny about it. So the Children created the Others and now winter is not only coming, it’s going to kill errbody unless Bran, Jon, Tyrion, Arya, and Daenerys do something about it. Or Howland Reed. What if that is the next Hero in the form of a Green Man? We’ll just carve that one in the weirwood tinfoil tree for now.
And now that Bran is the Three-Eyed Raven, he needs to learn to control his powers and fast. Enter long lost Uncle Benjen now as Coldhands. The Children saved Benjen from his White Walker injuries by sliding a dragonglass knife in his wound. Yep. The very same way they made the first White Walker. So is Coldhands immortal? Does he have super powers too besides that cool fireball on the end of the chain thing? Whatever else he can do, Coldhand's main goal is to get Bran up to speed so he can play his part.
Let’s look at the origin of the Children of the Forest, what drove them to create these icy jerks, and the unstoppable war.
The Children of the Forest were the original inhabitants of Westeros. They were here thousands of years ago, when there were vast swaths of forests. They were non-human and small in stature and only grew to about the average height of a child. They have been described by giants as “little squirrel people.” They preferred the crannogs, caves, and deep forests. Their forest dwelling earned them the name the Children of the Forest, or the Children.
They worshipped the Old Gods of the Forest, all of the spirits of every rock, river, stream, plant, and tree. The weirwood tree was a large part, if not the central part, of their rituals. The Children carved the faces in the weirwood trees and considered them sacred. Their priests are greenseers.
The Children made peace with the First Men called The Pact at the Isle of Faces at the center of God's Eye lake, agreeing that the humans would have the open lands and the Children would be given back the forests. The peace lasted 2,000 years.
And then he was Coldhands! Benjen is gravely injured by the White Walkers and the Children push a dragonglass knife into his wound and brought him back, using the very same method to create White Walkers in the first place.
Benjen has worked with the Three-Eyed Raven to look over Bran from a far. He helped Bran come into his full powers, but was ulimately slain in Season 7 by the army of the dead.
About 2,000 years into the Pact, the peace was interrupted by the White Walker invasion, when Walkers killed both men and Children in great numbers. The First Men and the Children came together to fight the White Walkers.