Rhaenyra Targaryen is easily one of the more complex of the bunch. The daughter of Viserys and the only surviving child of Aemma Arryn, Rhaenyra is named her father's heir, ultimately fueling the Targaryen civil war. Things are far from easy for Rhaenyra as she tries to find her way in the world.
Spoilers ahead for House of the Dragon.
One of several interesting connections between Game of Thrones and House of the Dragon is how the early Targaryen rulers saw dreams of White Walkers and a long winter, passing it along the generations. When Viserys sets his mind to naming Rhaenyra as his heir, he subsequently passes this burden of knowledge to his daughter.
This is a secret that has been successfully passed down from one king to the next, but with Rhaenyra's reign being doubted and challenged, this could put the passing of the message in danger. The fact that it isn't a known secret in Game of Thrones shows that the tradition of passing the message on through generations must have died at some point.