- "Though Lady Ellyn was no longer welcome at Casterly Rock, Tytos didn't refuse her brothers Roger and Reynard Reyne, not even when they asked for extravagant loans."
- ―Jaime Lannister
With their sister Ellyn Reyne unwelcome at Casterly Rock due to her attempted affair with Lord Tytos Lannister, Reynard and his brother Roger Reyne met with the lord to asked him for extravagant loans. Lady Ellyn then used the gold they had been granted to restore Tarbeck Hall to its former splendor. Lord Tytos approached them for repayment and they laughed at him, with Tytos soon laughing along with them.
Following his return from the War of the Ninepenny Kings, Tytos's son Tywin Lannister was determined to re-establish House Lannister as the dominant house in the Westerlands and demanded that all debts owed to them be paid immediately or a hostage from those who could not. Reynard merely laughed when he received the raven.
Tywin later marched on Tarbeck Hall and Castamere with an army behind him. Upon seeing them approach Tarbeck Hall, Ellyn sent ravens to her brothers at Castamere. Roger's army reached Tarbeck Hall just in time to see it consumed by flames. He charged Tywin's camp, hoping the element of surprise would overcome Tywin's greater numbers. Half of Roger's men were killed and he received a crossbow bolt to the back before he fled back to Castamere. Tywin's host arrived three days later and the Reyne brothers retreated into the underground mines and offered terms to him to avoid a long siege. Tywin gave no reply and ordered the mines to be sealed with stone and soil to prevent them from escaping. He then had the stream beside the castle dammed and directed to the main entrance, drowning the brothers. Their deaths inspired the song "The Rains of Castamere".
In the books
In The World of Ice & Fire, Ser Reynard Reyne was a charming and cunning man who was less headstrong than his brother Roger Reyne. The brothers were often present at Casterly Rock during their sister Ellyn Reyne's marriage to Tion Lannister. They returned to Castamere following Tion's death as his younger brother Tytos Lannister was groomed for leadership by their father Lord Gerold Lannister. Ellyn later wed Walderan Tarbeck, Lord of Tarbeck Hall.
It has been claimed that in 255 AC House Tarbeck angered King Aegon V Targaryen with their territorial demands. Lord Tytos sent Lord Denys Marbrand to capture them, but he and his men were killed when they were ambushed by a force led by Roger. Reynard convinced Tytos that Roger had mistaken the men for outlaws and Tytos pardoned both the Reynes and Tarbecks.
Tywin Lannister returned from the War of the Ninepenny Kings and attempted to restore order to the Westerlands. Roger oversaw the safe exchange of hostages held by House Lannister and House Tarbeck at Castamere.
During the Reyne Rebellion, Tywin killed Lord Walderan in the field and destroyed Tarbeck Hall. House Reyne's army attacked Tywin's, but were overpowered by their greater numbers. Reynard took charge of the army once Roger had become feverish after a crossbow wound and was incapable of leading.
Reynard led the Reyne force back to Castamere and had them retreat into the underground mines. It has been said that he offered peace terms to Tywin if Tywin's brothers were sent into Castamere as hostages. Tywin refused the offer and ordered his men to barricade Castamere's entrances with stone. He then had them redirect a nearby stream into the castle, flooding it and drowning the remaining members of House Reyne.