Credit: HBO

Game of Thrones Season 4, Episode 4, “Oathkeeper,” had a startling reveal in its closing scene. In it, we discovered how the mysterious White Walkers are created, which came as a shock not only to watchers of the show, but also to readers of the A Song of Ice and Fire book series, since that detail had not yet been revealed in the books. So, where do they come from?

In the scene, we saw one of the Night’s Watch traitors, Rast, leave Craster’s last son in the woods as a sacrifice for the White Walkers. This tradition had been seen before on the show, with Craster himself performing the task. We knew the White Walkers took the babies, which ensured some kind of truce with Craster, but we never knew what the supernatural beings did with them. Now we do.

The final shot of the episode showed a White Walker taking the baby to a ceremonial ice altar, possible in the Land of Always Winter. Then, what appears to be the King of the White Walkers (complete with a crown growing out of his head) approached the baby and touched him on the face, turning the baby’s eyes ice blue as his skin withered and grayed. In other words, White Walkers create new White Walkers from human babies. The more you know.

Were you shocked by this revelation? Let us know in the comments below!