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.