[b][u]House Greyjoy[/u][/b]
[img]https://vignette3.wikia.nocookie.net/gameofthrones/images/8/86/House-Greyjoy-Main-Shield.PNG/revision/latest/scale-to-width-down/350?cb=20170523015836[/img]
[b]Seat: Pyke
The Iron Islands[/b]

[img]https://vignette3.wikia.nocookie.net/gameofthrones/images/e/e1/Dalton_the_Red_Kraken.png/revision/latest/scale-to-width-down/350?cb=20161119182635[/img]
[b][u]Dalton Greyjoy, the Red Kraken[/u][/b]

The eldest son of the Lord Reaper of Pyke, Dalton Greyjoy was known to be wild. He first started rowing and the age of five, and at the age of ten began reaving alongside his uncle. He became an experienced reaver, having fought in several battles, and sailed to lands such as the Basilisk Isles and Old Ghys. By the time he was fourteen, he had already claimed four salt wives and owned a Valyrian steel sword named Nightfall, which he had acquired from a dead corsair.

When he was fifteen, he watched his uncle die in battle. Dalton managed to avenge him, but not without taking a great number of wounds, emerging covered in blood, and earning the nickname 'the Red Kraken.' 

When his father died that same year, Dalton returned to the home to claim the Seastone Chair, becoming Lord of the Iron Islands. His first act had been to expand the Iron Islands' navy - constructing longships, forging swords, and training soldiers. His reason for doing so had been, in his own words: "the storm is coming." At the age of sixteen, when news of the war broke out, he laughed.

[b][u]History[/u][/b]

The Iron Islands are located off the western coast of Westeros - more specifically, west of the Riverlands. There are thirty-one islands overall, and it is the smallest region in the Seven Kingdoms. They have a rocky landscape with poor soil, scarce natural resources, and frequent storms. They are home to the Ironborn, who are a primarily seafaring people that excels at sailing, fighting, and raiding. For thousands of years the Ironborn have raided the mainland, in order to compensate for their own lack of wealth and resources, but they do engage in trade. Slavery is legal in the Iron Islands, referred to as thralldom. The dominant religion in the Isles is worship of the Drowned God, and their priests are called Drowned Men. A common saying is "What is dead may never die, but rises again harder and stronger."

The Greyjoys were among the oldest and most powerful Houses in the Iron Isles, claiming to be one descended from the Grey King, a legendary figure in Ironborn history. Their house words are "We do not sow." The Greyjoys were bested only by Houses Greyiron and Goodbrother when it came to number of Kings chosen by the Kingsmoot, an ancient tradition in which the Ironborn lords and captains elected their own ruler to serve as King of the Iron Islands. The position was not hereditary, and another Kingsmoot was to be held upon when the recent King died.

Unfortunately, the tradition of the Kingsmoot would eventually be ended by the Greyirons. Eventually the Greyiron Dynasty would enter a decline after the invasion of the Andals, being replaced by the Hoares. Centuries later, King Harwyn Hardhand would go on to conquer the Riverlands, and his grandson, a tyrant known as King Harren the Black, would construct a massive castle named Harrenhal. During Aegon's Conquest, Aegon Targaryen successful managed to incite a Riverlord revolt against King Harren's rule. Aegon then used his dragon to raze Harrenhal to the ground, killing Harren, his sons, and most of his supporters.

The Ironborn lost the Riverlands, which Aegon then granted to the Tullys. Eventually Aegon would conquer the Iron Islands themselves, but would allow the conquered Ironborn to choose Vickon Greyjoy as Lord of the Iron Islands. Afterwards, the Ironborn would mainly keep to themselves, staying out of politics and no longer permitted to raid mainland Westeros.

Note: I'm not 100% well-versed in Ironborn lore and had to make use of numerous wikis. Sorry if there are any inaccuracies.