Thoros

Thoros of Myris a red priest of R'hllor from the Free City of Myr, and a member of the court at King's Landing.

There is currently no information if he will be cast. But his good friend Ser Beric Dondarrion has already appeared.

Cripples, Bastards and Broken Things
He is mentioned during a conservation between Jory Cassel and Jaime Lannister. They reminiscence about the Siege of Pyke and mention that Thoros of Myr charged the breach with his burning sword.