The series revealed Aegon the Conqueror as the owner of the catspaw dagger (spoilers ahead)
House Of The Dragon season 1, episode 4 has brought more changes to how the Night King from Game of Thrones died. Since the events take place two centuries before Game of Thrones, the prequel does have power and impact. One such example is how the prequel revealed that Aegon the Conqueror dreamed of White Walkers, thereby changing House Targaryen’s whole history and purpose in Westeros.
House Of The Dragon On The White Walkers
In House Of The Dragon, we learned that Aegon decided to invade Westeros due to the coming Winter, and that line made it more interesting on how Jon Snow and Daenerys contributed to the Night King’s defeat and the end of the White Walkers. This suggests that Jon was indeed the hero of prophecy and that Dany’s true purpose was to unite the warring kingdoms to team up against the Walkers. She was never meant to sit for long on the Iron Throne. The dream of Aegon was connected to Prince That Promised prophecy, and in its wake, revealing that the catspaw dagger’s previous owner was Aegon.
House Of The Dragon reinforced the importance of the catspaw, but changed the Night King’s death. In the finale of Game of Thrones, Arya Stark kills him with the catspaw dagger. The dagger being the Night King’s killer was connected to Aegon’s Song of Ice and Fire dream. The Walkers were prophesied to be defeated by the Targaryens.
This connection was indeed epic, but GoT showrunners David Benioff and D.B. Weiss did not choose Jon as the Night King’s killer because it seemed too obvious. Jon was always saving the day, so giving it to Arya seemed better. But House Of The Dragon stands by the belief that it should’ve been a Targaryen that got the job done. In the end, it can be summarised that prophecies may not happen accurately.