TV series, the primary White Walker has been portrayed by Ross Mullan. The show calls them "White Walkers" to avoid confusing "the Others" and "others" in speech. Their apparent leader is the Night King, portrayed by Richard Brake and Vladimir Furdik, who first appeared in the episode "Oathkeeper", in which he places his hand on Craster's baby son, transforming him into a White Walker. In "Hardhome", the effectiveness of Valyrian steel against the White Walkers is proven as Jon shatters one to pieces with a single stroke of his ancient sword Longclaw. Unlike in the novels, the TV series has established that wights can be destroyed by dragonglass. 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. In the eighth season premiere, "Winterfell", a group of survivors from the Wall's destruction discover that Last Hearth, the home of House Umber, has been attacked by the Army of the Dead in their conquest of the North, with all of its inhabitants killed. The Night King has also left a message in the form of the deceased Ned Umber impaled on a wall and surrounded by a spiral of severed limbs. In the second episode "A Knight of the Seven Kingdoms", the inhabitants of Winterfell make plans for defending the castle against the Army of the Dead. Bran states that the Night King is seeking an "endless night", as he plans to cleanse the world of all life and memory and intends to kill Bran as a major step towards this goal. The White Walkers are later seen viewing Winterfell from a distance as the living prepare to fight them. In the third episode "The Long Night", the Army of the Dead marches on Winterfell