Randyll Tarly

Randyll Tarly is a character in Game of Thrones. He has not been cast yet and has only been mentioned in dialogue. He does appear in the books, so may eventually appear in the TV series.

Lord Randyll Tarly is the head of House Tarly, a vassal of the Tyrells of Highgarden. He is a fierce, ruthless warrior and a highly effective general. He is the father of Samwell Tarly and a younger son, Dickon, as well as several daughters.

Furious with his elder son and heir Samwell's 'womanly' interest in poetry and singing and disdain for martial valour and combat, Randyll told Sam to take the black and join the Night's Watch. If not, he'd be found dead one day in a hunting accident. Sam did as he was bid and left Horn Hill for the Wall.

In the books
In the Song of Ice and Fire novels, Lord Randyll Tarly is considered the best battlefield commander in the Seven Kingdoms, a general able to read the ground, weather conditions and how a battle is progressing with impressive accuracy. During Robert's Rebellion he inflicted Robert's greatest defeat, routing his forces at the Battle of Ashford. During the later stages of the rebellion he helped Lord Mace Tyrell besiege Storm's End, and bent the knee after the death of King Aerys II Targaryen. He is said to be utterly merciless to his foes and wields the Valrian steel blade Heartsbane in battle.