Gwin is the only daughter of Alannys and Damron Greyjoy, and their youngest child. She is a headstrong woman and a talented archer.
Gwin Greyjoy fought alongside her mother and her brothers in the Reaper's War .
Gwin led a series of raids against the North at the command of Loren Lannister and her mother. She was captured by Dacey Mormont while attacking Bear Island. Her mother eventually led a small group of ironborn in a rescue mission, freeing Gwin.
During the War of the False King, Gwin was ordered to remain in Pyke and assist her brother with the ruling of the islands while Alannys Greyjoy and Dagon Greyjoy fought battles in the Reach. While on Pyke, she learned of her mother's intent to marry her to Quellon Goodbrother, and fled, headed for Lonely Light. She was captured by the Drumms after wrecking her ship in the harbor due to fog.
Gwin was given command of the Iron Fleet after Baron Harlaw demanded Dagon be stripped of the title for the death of Tristifer Harlaw. She was imprisoned on Pyke to await her marriage, but Urron helped her escape, along with Masha Drumm and Quellon himself. She traveled to Lannisport, and then boarded a ship for Lys.
In Lys, Gwin was hired by a Lyseni merchant girl named Rhaena.
"The young Greyjoy was a buxom woman, no older than twenty five, with wide hips and long legs that let her stride alongside any man and match his pace easily. She was fortunate to look more like her father than her mother. Gwin would be considered pretty for an ironborn woman, which is to say that she wasn't very pretty at all." - Blood and Whispers
"The next time that you wake me for some rambling madman, I will put you in a gown and ship you off to the green lands where you will find women just as empty headed as you are. Would that make you happy?" - Alannys Greyjoy
"I am not meant for the chains of marriage. I am above such bonds. I will choose my own lover, I will chart my own course."
“I’ve been called a lot of things in my life. Smart is not one of them."
Alannys Greyjoy, mother
Damron Greyjoy, father (deceased)
Gwynesse Lannister, aunt (deceased)
Merryk Greyjoy, brother (deceased)
Aeron Greyjoy, brother
Dagon Greyjoy, brother