Appearance and Personality
Euron was considered by many to be the most handsome of the Greyjoy brothers, and even now he looks much younger than any of them. With pale skin and hair as black as night and a beard, Euron is noted to be tall and well-built. Euron's most distinctive feature is his eye - he wears an eyepatch over one eye, and the other is described to be bright blue. His lips are also a pale shade of blue, since he developed a tendency to drink shade of the evening and gained these blue lips as a side effect.
Euron is highly intelligent, cruel and dangerous in more ways than one. An extremely cunning man by nature, Euron is ruthless enough that he has developed a reputation as the worst of all the Greyjoys - he was responsible for most of the strategic actions during the Rebellion, and hugely enjoys playing psychological games with any enemy he can get his hands on. He is a fierce warrior and a seaman of the finest calibre, albeit mostly down to his totally pitiless nature as well as his genius; Balon was the most ambitious, Victarion the strongest and Aeron the most devoted, but Euron is worse than any of them due to him being completely unscrupulous about what he does, and even abused his younger brothers when they were young. He has incited the permanent hatred of his brother Victarion especially, who has vowed to kill him but is stymied by the taboo of kinslaying and his indoctrinated sense of duty.
Euron possesses an effortless talent for leadership and charisma, and won over the other ironborn in the Kingsmoot because of how he expressed his awesome ambition, completely surpassing all of his competitors by appealing to the better nature of all ironborn, who were raised to believe that they were meant to reave and pillage and conquer. Euron was capable of turning his opponents' insults against them, as he did with the suggestion that he was godless, which he met by stating that 'from Ib to Asshai, when men see my sails, they pray', simultaneously bolstering his terrifying reputation. Euron was also sly enough to offer his crew the lion's share of his plunders, whereas most ironborn would reap the greatest rewards of their conquests.
Euron was crueler to his allies and subordinates than his enemies, as he cut out the tongues of his crewmen and thralls.
Euron fought with the rest of the Iron Islands to make his brother Balon Greyjoy the king of an independent realm and to bring about the return of the "old way".
At the beginning of the rebellion, Euron devised a plan to sail into Lannisport and burn the Lannister fleet at anchor. The plan was carried out by his brother, Victarion Greyjoy, who led the Iron Fleet and destroyed the Westerlands naval force.
Some time after the war, Victarion claims Euron raped his salt wife (though he claims she came to him willingly), and was banished by Balon, who warned him never to return as long as Balon still lived. Since his banishment, Euron has sailed his ship the Silence, which is crewed by mutes whose tongues Euron cuts out, to rape and pillage across the known world. Euron claims to have travelled to Asshai and beyond, and even to have sailed the Smoking Sea and walked the charred and smoking ruins of Valyria, where he found a magical Dragon Horn used by the Dragon Tamers of old Valyria to control dragons. He also once owned a dragon egg, but claims to have tossed it into the sea during a foul mood. Euron has fathered numerous bastards, many of whom are crew on his ship, but he has no regard for any of them.
Return to the Iron Islands
After his brother Balon fell to his death while crossing a bridge in a storm, Euron sailed into Pyke on his ship and claimed the Seastone Chair for himself. When Lord Botley objected, Euron had him drowned in a cask of seawater. Some found the timing of his return suspicous, since Euron was supposedly sailing far away seas, yet returned the very day after his brother died.
Euron's brother Aeron called a Kingsmoot, an ancient gathering to choose a new king, in order to remove Euron from power, hoping to make his brother Victarion king instead. Victarion, Euron's niece Asha, and various other contenders all made their case, but it was Euron who won the election by demonstrating his Dragon Horn and promising that he would conquer all of Westeros for the Ironborn by using it to bind the dragons currently in the possession of Daenerys Targaryen to his will. When Baelor Blacktyde refused to accept Euron as his king, Euron had him killed.
Euron began raiding the Reach to great success, capturing the Shield Islands. Euron weakened potential rivals by giving lands and titles to their key supporters. He sent his brother Victarion and the Iron Fleet to find Daenerys Targaryen and court her in Euron's name, and bring her dragons to Westeros. He gives Victarion the Dragon Horn to take with him to Daenerys.