Alys Rivers will be a key player in 'House of the Dragon' if her story follows the plot of 'Fire and Blood.' Here's what to know.

Source: Business Insider

Gayle Rankin as Alys Rivers in "House of the Dragon" season three. Ollie Upton/HBOAlys Rivers is introduced in "House of the Dragon" season two as a mysterious resident of Harrenhal. In the book, "Fire & Blood," Alys is a mysterious character who's suspected of being a witch.