Randyll is a renowned and almost legendary commander of soldiers and armies, but that is his one and only redeeming quality. He is unspeakably cruel to his eldest son Sam, and has been his entire life, so much that he actually confessed that nothing would please him more than hunting Sam down if the latter didn't take the black and renounce his claim to Horn Hill. A pitiless and utterly warlike man in the best of times, Randyll easily resorts to violent and sadistic punishments that (strangely) seem to match the crime. He is considered both dangerous and invaluable because of his ruthlessness. Randyll is also an especially proud man, hence his devotion to raising Dickon Tarly to become the prospective lord of Horn Hill.
In the BooksEdit
After King Robert's death, he joined his liege lord, Mace Tyrell, in supporting Renly Baratheon. In the early stages of the War of the Five Kings, he advised Brienne of Tarth that the men had placed bets on her virginity, as well as advising her that women have no place on the battlefield. He also fought with House Lannister at Blackwater against Stannis Baratheon.
He marched from Maidenpool to King's Landing after hearing that Margaery Tyrell had been imprisoned on the command of Cersei Lannister. From there, he was named as a good candidate for Hand of the King, but Mace Tyrell took the position instead.