Spoiler - Lightbringer = Valyrian Steel Recipe
I wanted to share a theory I have that I am probably sure someone else has had, but I am not sure if its been posted here.
I think the story of Lightbringer could be the long lost recipe to create Valyrian Steel. Maybe these blades demand a human sacrifice of or blood magic. I believe the Valyrian Freehold had great excesses of slaves to supply for their blacksmiths with the required sacrifices.
I am curious if anyone has any thoughts on what that may mean for the final season if they come to the conclusion that more Valyrian weapons are needed or even a new Lightbringer, though it seems the show seems focused on dragon glass.