House of the Dragon has introduced Alysanne Blackwood, a fierce archer fighting for Rhaenyra's cause, in a moment that reshapes the show's ongoing war storyline. Although actress Annie Shapero was announced for the role ahead of Season 3, the character only made a significant impact in Episode 6, when she killed Ser Criston Cole, the Kingsguard Lord Commander and Hand of the King, during an ambush by the Rivermen and Winter Wolves.

Alysanne, also known as Black Aly, belongs to House Blackwood and serves in the Riverlands army recruited by Daemon Targaryen, despite not appearing in Season 2. In the show, she kills Criston with three arrows fired from the treeline after he challenges the rebel leaders to single combat, a departure from George R.R. Martin's book Fire & Blood, in which she is not directly responsible for his death but instead avenges her brother, Lord Samwell Blackwood, by killing Amos Bracken at the Battle of the Burning Mills. She subsequently commands archers within the Riverlands host, and the article suggests she is set to play a further important role as the series progresses.