Game Of Thrones: 8 Moments That Foreshadowed SPOILER'S Death
7. "Kill Him, He Turned Them All"
Looking at the Night King's death, we learned of why he had to die in Season 7, when Beric Dondarrion tells Jon: "Kill him," he says, pointing at the Night King. "He turned them all."
Killing the Night King does indeed work, with all of the White Walkers and wights dying alongside him, just as Beric predicted.
It's important that it was Beric who noted this too. He might say it to Jon, but this season has built up his connection to Arya and the Hound more so, including in The Long Night. There, when the Hound tells him they can't beat death, Beric simply points to Arya and says "tell that to her."
Beric died so that Arya could kill the Night King, which isn't technically the first time he's died for her (his trial by combat with the Hound in Season 3 is because of her), but is the last. He's long spoken of the Lord of Light's purpose, and now we know it was to protect Arya, allowing her to kill the one who turned them all.