Euron is the younger brother of King Balon Greyjoy, older brother of Aeron Greyjoy, and the eldest uncle of Theon and Yara Greyjoy.
Euron Greyjoy is the younger brother of Balon Greyjoy, head of House Greyjoy, Lord Reaper of Pyke and self-fashioned King of the Iron Islands.
Euron has spent the last few years as a pirate, reaving from Oldtown to Qarth and beyond. He once lost his senses during a storm whilst sailing on the Jade Sea, and his crew was forced to tie him to the mast to prevent him from jumping overboard. When he was let down after the storm, he had all their tongues ripped out.
Tyrion Lannister tells Theon about his memories of witnessing the Raid on Lannisport which Tyrion says was caused by Theon's uncles
Euron returns to the Iron Islands following the War of the Five Kings, arriving during a violent storm. He confronts Balon, who believed Euron to be dead, on one of the rope bridges of Pyke, saying the ironborn words of “what is dead may never die”. When Balon accuses him of mocking the Drowned God, Euron retorts, boasting that he is the Drowned God, for whenever men see his sails they pray. Balon notes that Euron lost his mind during a storm, and Euron tells him that he is “the storm”, prompting Balon to attack him with a knife. Though Balon wounds his face, Euron easily overpowers his elder brother, and throws him off the bridge to his death.
Balon Greyjoy's younger brother Euron recently returned from years at sea to claim the Iron Islands as his own - by killing his brother. He unapologetically confessed to the murder at the kingsmoot, his plan to seduce Daenerys Targaryen with the Iron Fleet and use their combined forces to conquer the Seven Kingdoms won over the Ironborn.