Who kills Gregor Clegane?

Who kills Gregor Clegane? The show has been setting up a battle of revenge for The Hound since the beginning, because his brother is the one who scarred him as a child. But the way Sandor took down the seemingly insurmountable Gregor is kind of an epic callback.

The show has been setting up a battle of revenge for The Hound since the beginning, because his brother is the one who scarred him as a child. But the way Sandor took down the seemingly insurmountable Gregor is kind of an epic callback.