Jason Lannister son of Gerold
Not to be confused with Jason Lannister.
Jason Lannister was the youngest son of Lord Gerold Lannister and Lady Rohanne Webber, raised at Casterly Rock in the uneven shadow of his elder brother Tytos, who would go on to inherit the lordship.
He is remembered chiefly for the command he took of the westerlands host when the War of the Ninepenny Kings broke out, a post his battle-shy brother could not fill himself.
Chapter 1
The troublesome son of Casterly Rock
229–245 ACBooks only
Jason was the youngest of the four sons Lord Gerold Lannister had with his second wife, Lady Rohanne Webber, who vanished without explanation when he was barely a year old. He grew up at Casterly Rock, forever clashing with Tytos, the soft-willed brother destined to inherit the lordship.
At fourteen he got a serving girl with child, who bore him a bastard daughter, Lynora Hill. A year later he seduced Alys, the unmarried daughter of Lord Stackspear, and left her pregnant too; Tytos — pushed, it was said, by his wife Jeyne Marbrand — forced him to marry her. Alys died giving birth to a son, Damon.
Barely fifteen days after the burial, Tytos and Jeyne married him off again, this time to Marla Prester, a woman twice his age who would give him six more children. The couple settled far from Casterly Rock, at the Bonfires, a move that reportedly eased more than one mind back at the castle. As a boy he had been fierce; as a man he grew proud and quarrelsome, ready to belittle his own brother in private yet quicker still to anger if anyone else dared do the same.
Chapter 2
Command of the westerlands
260 ACBooks only
The War of the Ninepenny Kings broke out in 260 AC, and since Tytos had no stomach for soldiering, command of the westerlands host — a thousand knights and ten thousand men-at-arms — fell to Ser Jason, who led it to the Stepstones.
That same year he died at Bloodstone, officially of a bowel fever, though rumor held that Maelys Blackfyre had had him killed. Command of the host then passed to Lord Roger Reyne.
Gallery

Jason Lannister, image 2SOHN Jason Lannister Still.jpg · gameofthrones.fandom.com · this wiki publishes under CC-BY-SA 
Jason Lannister, image 32x8 Jason Lannister Still.jpg · gameofthrones.fandom.com · this wiki publishes under CC-BY-SA 
Jason Lannister, image 4The Golden Lord Lannister.jpg · gameofthrones.fandom.com · this wiki publishes under CC-BY-SA