I mean, I haven't seen it, but I suppose it's interesting, as long as it is canon. Another story/legend from SoIaF turning out to be real is no surprise to me though. And I'm less interested in the Night King and more in that woman, who sounds like one of the Others, that he married and was corrupted by. If the Others predate him, then he isn't really the leader, and greater forces are still at work. Most likely still Melisandre's Devil/Other.