I do not own Game of Thrones
"Every time a Targaryen babe is born, gods flip a coin and the world holds its breath."
The news about the city of Kings Landing turning into ashes shook all of Westeros as expected. The whole incident went unexplained as the second doom of Valyria. Forces that were fighting each other settled into an uneasy peace. Rhaella Targaryen was declared queen regent of the seven kingdoms. This is where the other side of coin showed its value. The Targaryens may have been mad occasionally but they were rarely if ever mediocre.
Rhaella who had been tortured in shadow of her brother-husband for so long finally showed her worth. First she spread rumors about divine punishment and the superstitious masses lapped it up. If you go against the divine authority of the dragons then this may happen she abolished the Kingsguard system. It had never protected her so the white cloaks might as well be decorations.
With capital gone, Dragonstone became the new capital. It made her family safer but at the same time it decreased their influence on the mainland, not just at that time but it would continue to decrease in the future as well. She also married Ser Bonifer Hasty who she had loved for a long time. These two decisions would turn the Royal family into nothing more than three-headed mascots. Many even stopped paying taxes.
The most troubling situation was about how to maintain law and order of the two kingdoms that lacked military entirely. The solution she came up with was unprecedentedly dangerous. She sold the empty castles to the Ironborn, Redwynes, Velaryons and others for their ships as well as any rights to create or board any ships in the future. In short, only Dragonstone would have a navy and the rest were not allowed to have any.
Normally the lords would have rebelled at that level of dictatorship but the offer was too good to pass on. It wasn't necessarily a good solution as piracy was still a thing. They crushed pirates with the now centralized navy but it could not be stamped out. Lords who felt unsafe about the coast or were too greedy to respect the royals restarted their navies in secret. It was difficult to keep them a secret on mainland unlike the Iron Islands so they were kept small and the queen ignored them as a minor problem.
New problems emerged over the years. The cities of Essos saw Westeros as a delicious target now that most of them did not have protection at seas. Even many slavery rings started to work from within the seven kingdoms to Essos, with Jorah Mormont and the Greyjoy family being chief amongst them. The faith of the seven had started to get their grip back by changing the narrative. The divine punishment came from the seven according to them, it was against the dragons and not for them. It started to rise as the faith militant which countered slavery as well as the royal family.
The queen had three healthy children with Ser Bonifer even after Daenerys proving that the pregnancy problem was not with her but with incest. The children were named Aemon, Daeron and Visenya. While she was capable, she was still a mother so most of her decisions were defensive and peace oriented. She was able to measure and avoid the bottom line of most nobles but always had to compromise to avoid another.
Until the dragons hatched.
The former Kingsguard
Gerold Hightower- Was assigned a castle in Dorne. Started a branch family called Lowtower out of shame for leaving the white cloak while living.
Lewyn Martell- Became the new Prince of Dorne to protect Elia and her children.
Jonothor Darry and Barristan Selmy- Took the black.
Oswell Whent- Became lord of Harrenhal. Repairing it was impossible but covering it up was not. He started preparing it hoping the queen will feel confident to use it as capital one day.
Jaime Lannister- Went back hoping to protect Casterly Rock but it already belonged to the Greyjoys. Cersei had married Euron at the condition of strangling Tyrion, which he gladly did. She in turn seduced and killed Balon. Jaime and Euron had single combat where both died. Then Cersei gladly married Victarion, hence tasting all three brothers.
Arthur Dayne- Ashamed of his assignment, he did not leave for Essos but rather went to Starfall. Ashara convinced him to take her and Lyanna to the North. Arthur and Lyanna were exiled to the neck where they fell in love and had Jon Snow without marriage. He would become the next wielder of dawn.