The best change House of the Dragon ever made from George R.R. Martin's Fire & Blood was making Rhaenyra Targaryen (Emma D'Arcy) and Alicent Hightower (Olivia Cooke) childhood friends.
The pair's new shared history and love for each other made their eventual enmity hurt even more, as these two fierce companions were torn apart and pitted against each other by the male-led systems of power in Westeros. As a result, any scenes they shared crackled with thorny resentment, not just at each other...