One of the most significant battles in Game of Thrones lore would be the Battle of Redgrass Field, which was the deciding battle of the first Blackfyre Rebellion. Daemon Blackfyre, the First of His Name, and his two eldest sons were slain in this battle while his surviving children and some of his followers fled into exile. Daemon’s surviving supporters who could not escape into exile lost lands, titles, and had to surrender hostages to the Iron Throne to guarantee their future loyalty. Even though Daemon was dead, his descendants still fought for the Iron Throne in four more rebellions until the last of his male descendants, Maelys the Monstrous, was slain. The fate of Daemon’s descendants from the female bloodline is unknown.
However, even though the story of Game of Thrones went the way it went, I am always curious of how the story would have turned out if Daemon Blackfyre won the Redgrass Field and overthrew the Targaryen Dynasty. What kind of world would Westeros be if it was ruled by a Blackfyre Dynasty instead of a Targaryen one. One of Daemon’s supporters made multiple notes of how the battle could have turned out differently. If Daemon left Gwayne Corbray to his fate after defeating him instead of trying to rescue him, if Fireball was not slain on the eve of battle, if Lord Bracken was not stalled by storms while transporting Myrish crossbowmen from Essos, and so forth.
If House Blackfyre ruled the Iron Throne, the alliance that Baelor the Blessed and Daeron the Good tried to forge with Dorne would have been destroyed. One of the reasons so many sided with Daemon was because they were unhappy with the peace Daeron the Good was promoting and they wanted a warrior like Daemon as their king. With the Blackfyres in charge, the Iron Throne would be waging never-ending wars against Dorne that would cause more loss of life like when Daeron the First tried to conquer Dorne. With these events happening, I think the story of Game of Thrones would become less like the War of the Roses and more like the War of Scottish Independence. Overall, I think a Blackfyre Dynasty would be an interesting alternate reality of the Game of Thrones universe that is worth exploring.