Deadline reports that Jeanine Mason, an American actress and a former contestant on So You Think You Can Dance, will play Merav, who was played by South African actress Alex McGregor in the original pilot (and in the trailer).
Merav is the daughter of King Saul (played by Ray Winstone) and his wife Ahinoam (Simone Kessell), and she is also the sister of Michal (Maisie Richardson-Sellers), Jonathan (Haaz Sleiman) and Ish-Bosheth (James Floyd).The biblical Merav also had brothers named Abinadab and Malki-Shua, but I do not know if those characters will be featured in this series.
In the Bible, King Saul offered to let David marry Merav, possibly as a reward for killing Goliath. But David turned the offer down, and Merav married someone else instead. Shortly afterwards, David married Merav’s younger sister Michal.
Then, many years later, when David was king of Israel, he allowed a tribe called the Gibeonites to kill Merav’s five sons so that a curse would be lifted from the land.
I wouldn’t expect this series to cover the entire story of David’s kingship — it would require the actors to age several decades over the course of just a few seasons, for one thing — but I wouldn’t be surprised if some of that morally murky stuff from those later stories informs how the characters are developed in these earlier episodes.
— The photo at the top of this page is from Mason’s Twitter profile.