SPOILER: They gon' die. Most of them. Probably. At some point.
At the SDCC panel for their smash hit HBO series, creators and producers of Game of Thrones announced the latest set of new actors who will spend an unspecified amount of time being alive in Westeros. Notably, a decent faction of the new actors are portraying members of Oberyn Martell's previously-mentioned extended family.
The new meat will include:
Jonathan Pryce (Brazil, G.I. Joe) as the High Sparrow
Rosabell Laurenti Sellers (Italian televsion actress) as Tyene Sand
Keisha Castle-Hughes (Whale Rider, The Nativity Story) as Obara Sand
Jessica Henwick (BBC's Spirit Warriors) as Nymeria "Nym" Sand
Alexander Siddig (Star Trek: DS9) as Doran Martell
Enzo Cilenti (Kick-Ass 2) as Yezza
Toby Sebastian (Barely Lethal) as Trystane Martell
Nell Tiger Free (replacing Aimee Richardson) as Myrcella Baratheon
DeObia Oparei (Dredd) as Areo Hotah