
He killed a White Walker.
Game of Thrones Season 6, Episode 6

Why would obsidian kill a Walker?
Game of Thrones Season 5, Episode 5

Killed a White Walker, eh?
Game of Thrones Season 5, Episode 7

But I'm told you killed a White Walker.
Game of Thrones Season 5, Episode 5

It's what I used to kill the White Walker.
Game of Thrones Season 5, Episode 7