Looking at a couple of the people they are casting for - I have no idea who the young Northern girl is meant to be, they are looking for an 8 year old. The boy has been described as Could it be for Gendry flashbacks ie to a time he was an apprentice to Tobho Mott and might have seen Valyrian steel being reforged?
Not if the young actor's hair could be dyed. The eye colour would probably be more important. However they might not want to give away that big a clue.
Why would they need to flashback to that, though? It was already established in Two Swords (S4, Ep1, I think) that Valyrian steel can be reforged (when Twyin had Ned's Ice turned into 2 new swords).
^Sounds more like one of Varys's or Qyburn's "little birds" to me. With so few episodes left I can't see them spending much time on more character backstory than is absolutely necessary.
The show also states that only three men in the entire world are capable of reforging Valyrian steel and none of those are anywhere near the north. If they need to reforge or make new Valyrian steel Gendry might be the only person available to them. It is clearly stated in the books that Tobho Mott could reforge it. Some people think that Ice might be the answer. Either it was Lightbringer or it could be the new Lightbringer. If so Widow's Wail and Oathkeeper will have to be reforged into being one sword again. I think Gendry has been bought back into the show for his blacksmithimg skillls moreseo that for being the son of Robert Baratheon.
Even if that's the case, I don't think it requires a flashback. We already Gendry is a capable blacksmith. If he's able to forge Valyrian steel, then a line or two of him telling Jon or whoever that his master taught him to do it will suffice. Plus Gendry has never been a "dominates every scene" sort of character as this casting note calls for.
If he only saw it as an 8 year old, which is plausible as reforging of Valyrian steel would be rare, than maybe Bran can go back and 'remember' for Gendry. Otherwise it is introducing a totally new character and I cannot really see why new children would be so important at this time. The girl seems to be very similar to Lyanna Mormont.
Here is a fan video that agrees with me about Gendry reforging Ice but it was made before season 7 and therefore before the casting call for this boy was made.
...which brings up the fact that Bran could easily view how Valyrian steel was first forged. "Reforging" would no longer be necessary as they could now make more.
Bran does not seem to know how to fully use his talent. He needed Sam to mention the wedding before he knew where to go and look. Àlso he has to send ravens to spy on the Night King suggesting he can't just do it remotely Maybe Bran does not know where to look for info on Valyrian steel.
It may not be possible. It's probably more than just a process, but also the raw materials required to make the alloy originating from pre-Doom Old Valyria.
Which would explain why it took Tobho Mott so long to reforge Ice into Oathkeeper and Widow's Wail for Tywin.
I think we have to also think about why the Targaryens were unable to forge new Valyrian steel after the Doom of Valyria. They had dragonglass and dragons so there had to be something else missing - either some knowledge or some ingredient. Maybe for the first time in more in 300 years all those people/ingredients needed to make VS will come together. Sam's knowledge from book , Bran's greenseering, Gendry's talent and practical knowledge, dragonfire and dragon glass and maybe the unknown secret thing.
IIRC from the books, it's just normal steel forged with spells and dragon fire. So really now that they have dragons, all they're missing are the spells. Anyway, I can't see how this would be a crucial plot point given that they have an apparently endless supply of dragonglass, which does just as well. Indeed, even more useful if it can be used to make arrowheads rather than just blades.
I think the idea is that he has access to all the world's knowledge and experience but it is not automatically downloaded into his brain. A good analogy would seem to be sitting at your computer with access to the world wide web. The information is out there but if you don't know what to look for then you are not going to find it easily. We can surf and browse randomly and find interesting things or we can look directly for information but sometimes we need to sift through a lot of things before we find what we're looking for. Also, has anyone else read the fan theories about Dany's origins?
I don't think they will need Valyrian steel to kill wights or White Walkers but it might either be needed to kill the Night King or to bring the Dawn. If it is needed to kill the Night King than it would be better if several more fighters have Valyrian swords in the hope that one of them reach the Night King. If a Lightbringrr needs to forged/reforged than Gendry will do it. I hope it will only need reforging, it is has to be forged than it will have to be a blood sacrifice most likely of Arya. As far as the show goes there is another possibility and that is Arthur Dayne's sword Dawn will be the Lightbringer. In the books Ned returns Dawn to the Dayne but in the show the last we see it is when Ned leans it against the bed in the Tower of Joy. Maybe it is in the Winterfell crypts? A concede that the show' might decide that Lightbringer is not a sword, or there is no Azor Ahai or Lightbringer. Some have suggested the Jon and Dany's baby will be the Lightbringer which is abn idea I hate.
Honestly, I don't think killing the Night King will be quite so straightforward. If it were then they would probably have done something similar in the age of heroes back when they had crazy magical powers. All they could do it seems is drive him back and (I think?) put him to sleep for 10,000 years. If this series of books has taught me anything, it's that GRRM loves to upend the usual fantasy tropes. So it almost baffles me how after everything else that's gone on that people still cling to the prophecy of the "Prince/Princess Who Was Promised" as a thing that'll actually play out. Remember the Stallion Who Will Mount The World? Yeah, his foretold reign of terror didn't even make it out of the womb. See also what went down with Stannis. Does Melisandre being *really* sure the second time around make her any less fallible? That aside, while it might play into the books more, it's too late in the game for the show to start introducing something like Lightbringer without it seeming like a total deus ex arse-pull. They just haven't done the legwork for it. Also, if it was *really* that significant to the endgame, you'd think GRRM might have tapped the showrunners on the shoulder at some point and whispered in their ears that maybe they might want to not skip Lightbringer.