In the season 6 episode "The Door" (May 2016), Bran Stark experiences a vision of the creation of the Night King by Leaf, one of the Children of the Forest, by stabbing a human prisoner in the chest with a dragonglass dagger. Leaf explains to an incredulous Bran that the Children were at war with the First Men at the time of the Night King's creation. In season 7, when Jon kills a White Walker, the wights under its control are also destroyed. The Night King kills Daenerys Targaryen's dragon Viserion in the seventh season episode "Beyond the Wall", and then reanimates him as a wight. In the season finale episode "The Dragon and the Wolf", the Night King uses the dragon to breach the Wall.