New teaser trailer released, featuring Matt Smith as Prince Daemon Targaryen, Emma D’Arcy as Princess Rhaenyra Targaryen, Olivia Cooke as Alicent Hightower, and Steve Toussaint as Lord Corlys Velaryon aka “The Sea Snake.” From the main characters and key locations to the showrunners and potential plot points, here s what to know about the George R.R. Martin–approved spin-off series.