Fae descended/ Lady of the Lake ish AU where Aegor never gets Blackfyre at Redgrass, because after Daemon, Aegon, and Aemon's deaths the sword just straight up vanishes before Aegor can reach it. He literally saw it vanish into the mud?!?! No one knows where it's gone or what happened to it but the assumption is that someone stole it, because Aegor never fucking says what he saw. Aegor's determined that it doesn't fucking matter and Daemon's kids still are the rightful claimants to the throne and continues to raise them with that thought in mind.
But where actually is Blackfyre? Well, you see, Dunk and Rafe went scavenging through the battlefield and came across this funky looking sword with its jeweled pommel. Rafe is... relatively certain the blade is made of Valyrian Steel but that doesn't make any sense because surely surely someone else would have scooped up the sword by now if that was true?!? Anyway, they take it with them. It ends up saving Rafe's life, because when Dunk realizing Alestor is going for her, he stabs him with the sword (it had been sheathed at his side, they'd covered the pommel and hilt with rags so no one would look at it twice). Dunk ends up killing the other two gold cloaks as well.
He and Rafe steal back their coin and all the extra coin the guards have on them and they go rushing off to get tickets to the Free Cities. But end up getting into some trouble before they can board the ship, Arlan saves them, and they end up going with him. Arlan keeps side eying the sword at Dunk's hip (because he was at Redgrass and he fucking recognises Blackfyre, thank you very much). Arlan's honour would demand he return the sword to the Targaryens, but his practicality means he knows he, Dunk, and Rafe would be accused of looting at the very least and likely end up being executed, so he says nothing about it other than a command for Dunk to keep the fucking thing hidden, unless Dunk's very life is in danger, and even then he better make sure not to let the Royal Family see it unless they're the ones threatening his life, and even then he better have some fucking luck on his side if he doesn't wanna lose his fool head over it. Dunk agrees, though he's confused about it (until he later realises the sword is Blackfyre).
Dunk loses Blackfyre approximately three times in the years with Arlan. Arlan'd be concerned about that except for the fact that the sword just... keeps on showing back up in the oddest places and it's always Dunk who stumbles over it again. He figures there's some magic at work here that he doesn't understand and it's not worth interfering with that. Just keep the sword safe, boy!
Arlan still ends up dying on the way to Ashford, but he does knight Dunk first, and Dunk and Rafe go on as normal and everything still happens as in canon. Except when Dunk's brought before Baelor regarding the whole Aerion situation, Dunk, who had discovered in his time with Arlan that he's something of a wordsmith if he puts his mind to it, ends up bargaining with Baelor, that if he can provide House Targaryen with something precious they've been looking for for years then Baelor will pardon Dunk and Rafe for any wrong doing already committed up to that moment. Baelor's very raised eyebrows about this, but agrees anyway on the condition that this 'something precious' must be very precious indeed, or the deal is off. Dunk just smiles and asks if Prince Baelor could request Dunk's arms be brought to them. Baelor, bemused, does.
Ser Arlan's sword and Dunks are brought to them by the guards and handed to Baelor. Baelor waits until the guards are gone and then he turns to Dunk and just asks 'now what?' Dunk grins and asks Baelor to unsheathe the larger of the two swords. Baelor does and furrows a brow at the Valyrian steel that's revealed. He looks up at Dunk demanding an explanation, but Dunk just tells him to take the rags off. Baelor does and just stares at Blackfyre, he hasn't seen it in well over a decade and what the actual fuck?!
"I believe, your grace, that I've just restored to you the symbol of kings. The King's Sword, if you will. I doubt you'll find something more precious to your house, except living dragons," Dunk says, the smile on his face is all teeth and Baelor realises suddenly what Dunk is. He's just bargained with a fae and the fae has kept their side of the deal and now Baelor... Baelor must keep his unless he wants to risk the fae's wrath. Dunk and Rafe get their pardon, but Dunk gains Baelor's unwavering attention.
Baelor later realises that Dunk has absolutely no fucking clue what he is, and he's determined to figure out how that can even be. How did the fae lose one of their children in fucking Flea Bottom of all places?!?! What the hell did Rafe mean when she said she was surprised the sword hasn't already abandoned Baelor?!? It's a sword?!?! What?!
