Bethany Bracken

Bethany Bracken is an unseen character in Game of Thrones. She is long dead before the start of the series, and thus is not expected to appear. Bethany Bracken was a member of House Bracken who lived during the reign of Aegon IV Targaryen.

History
Bethany Bracken was a mistress of King Aegon IV, the Unworthy. She was caught abed with Ser Terrence Toyne, a knight of the Kingsguard. King Aegon had Ser Terrence fed to his dogs.

In the books
In A Song of Ice and Firenovels, Bethany is indirectly referred to. Her identity was revealed by GRRM in an interview, which established her as Aegon IV's seventh mistress, and her backstory expaned in The World of Ice and Fire. Bethany Bracken was groomed from childhood by her father, who had been Aegon's Hand of the King, and her older sister, Barbra Bracken, to seduce King Aegon and replace Melissa Blackwood, which had in turn replaced Barbra as Aegon's mistress, thus restoring the king's favor upon House Bracken.

Bethany caught Aegon's eye, as his father and sister intended, when he visited Stone Hedge to visit Aegor Rivers, one of his bastard sons, and took her with him to King's Landing. However, Bethany found his "royal embraces" distressing, and turned to Ser Terrence Toynce for comfort and the two became lovers. They were caught abed by Aegon himself, resulting in the death by torture of Ser Terrence and the execution of Bethany and her father.