We think we know who the Night King is based off these hints…
1. He can ride a dragon and only Targaryens ride dragons.
2. The Symbols he is leaving look like the Targaryen dragon symbol.
— Evette ♡ (@Evette_V) April 15, 2019
Could Rhaegar (Jon’s father, Dany’s brother) somehow have been turned into the Night King??