Randyll Tarly

"You're almost a man now, but you're not worthy of my land and title. Tomorrow you're going to take the black, forsake all claim to your inheritance and start north. If you do not, then we'll have a hunt... and somewhere in these woods your horse will stumble and you'll be thrown from your saddle to die. Or so I'll tell your mother. Nothing would please me more."

- Randyll Tarly to his son, Samwell. Randyll Tarly is a recurring character in the sixth season, though he had been mentioned in every previous season. Randyll is played by James Faulkner. He is the Lord of Horn Hill and the head of House Tarly. He forced his son Samwell Tarly to join the Night's Watch under the threat of death.

Background
Randyll Tarly is the Lord of Horn Hill and the head of House Tarly, a vassal family of House Tyrell 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.

Along the his Tyrell overlords, Randyll fought on the Targaryen side in Robert's Rebellion. He commanded the royalist victory at the Battle of Ashford - the only defeat that Robert Baratheon ever suffered in the entire war.

Season 1
Samwell recounts to Jon Snow that even though he was his father's eldest son and heir, he was disgusted with Samwell's "womanly" interest in books and learning and disdain for martial valor and combat. Soon before Sam turned eighteen, his father took him aside and bluntly told him that he was unworthy to inherit the Tarly lands and titles. Randyll ordered Sam to take the black and join the Night's Watch. Randyll told his son that if he did not, he would take him out on a hunt in the woods and kill him in such a way that it looked like an accident. Terrified, Sam did as he was bid and left Horn Hill for the Wall.

Season 2
At Stannis Baratheon's war council, Davos Seaworth names Randyll Tarly amongst the many lords that have declared for Renly Baratheon.

Season 3
Samwell mentions his father by name when explaining the concept of family names to Gilly. When she points out that Randyll is a handsome name, he asks her to please not give it to her newborn son.

Season 5
Sam quips to Gilly that his father is not a very "literary man". Later, surprised that Samwell is Randyll's son, Stannis Baratheon recounts to Sam how Lord Randyll defeated Robert Baratheon in the Battle of Ashford — the only battle Robert ever lost, for which King Stannis considers Randyll a fine soldier.

In the books
In the A Song of Ice and Fire novels, Lord Randyll Tarly is considered one of the best battlefield commanders 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 only defeat while commanding the Tyrell vanguard 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 wields the Valyrian steel sword Heartsbane in battle and is said to be utterly merciless to his foes. Although a ruthless and stern man, he is not outright sadistic, often dispensing strict justice that is nonetheless within the bounds of the law.

During the War of the Five Kings, Lord Randyll commits himself to Renly Baratheon's cause, and Catelyn Stark encounters him when she visits Renly's camp to treat for Robb. When House Tyrell switches its allegiance to the Lannisters following Renly's death, most of their bannermen join them (except for essentially just House Florent): Lord Randyll follows his liege-lords, and House Tarly begins to fight on the Lannister side.

Lord Randyll treated Brienne of Tarth with open hostility while she was at Renly's camp. When he found out that several men laid wagers on the first to claim her maidenhead, he put a stop to it, but told Brienne offensively it was her fault because to his opinion women have no place on the battlefield.

In the books, while Roose Bolton was in charge of the eastern half of the Northern armies based at Harrenhal, he sent a large force of three thousand men (about a third of his command) east to attack the Crownlands. Roose had decided to betray the Starks by this point and was laying the groundwork for the Red Wedding and his subsequent takeover of the North, by intentionally killing off Stark loyalists by sending them on suicide missions. Coordinating with the Lannisters in secret, he sent his men into a trap set by a massive combined Lannister-Tyrell army, with Gregor Clegane commanding the Lannister forces and Randyll Tarly commanding the Tyrell forces. The entire Northern force was destroyed at the resulting Battle of Duskendale, all three thousand men, though a few Northern lords were taken prisoner.

Subsequently, Lord Randyll marches his army north from Duskendale to Maidenpool (east of Harrenhal, in the northeasternmost corner of the Riverlands) and easily takes the town. Unlike Gregor's Lannister men, who are more concerned with pillaging the already ravaged countryside, Randyll has his forces in Maidenpool set about fixing damage the town suffered in the war and reimposing law and order. He is very strict but not abusive, executing confirmed bandits and deserters who were raiding the smallfolk of the countryside, in order to discourage other outlaws from making further unrest.