House of the Dragon showrunner Ryan Condal says season three deliberately departs from George R. R. Martin’s Fire & Blood where doing so better serves television drama. The adaptation also brings the Prince That Was Promised prophecy into public view, linking the Targaryen civil war more directly to the wider Game of Thrones story and giving characters another motive beyond the struggle for the throne.

Condal argues that Fire & Blood is presented as an incomplete, competing historical record rather than a definitive account, leaving room for the series to interpret events and fill gaps. The prophecy, also known as A Song of Ice and Fire, concerns a future threat from the North and the belief that a Targaryen ruler must help unite the realm against it; in the series, it has become particularly important to Rhaenyra’s decisions.