When you killed the White Walker,
Game of Thrones Season 7, Episode 6
It's what I used to kill the White Walker.
Game of Thrones Season 5, Episode 7
Where did he kill a White Walker?
Game of Thrones Season 6, Episode 6
(WHITE WALKER SNARLING)
Game of Thrones Season 6, Episode 5
used one of these daggers to kill a Walker.
Game of Thrones Season 5, Episode 8