The Seven are gods of weakness and defeat, pretty chains that the First Men kindly put on after the Andals crushed them, except in the Iron Islands. Since the Dawn Age, the Ironborn have followed the Drowned God, who plucked fire from the sea and made them to reave and sack and write their names in blood and song.
When the Andals landed on the Iron Islands, they found a god who was Father, Warrior, and Stranger, who took Mother, Maiden, and Crone when he would, and held the Smith in thrall. His priests are Drowned Men, who are clothed and armed by the sea itself. They consecrate their people to the Drowned God through their most sacred right, the Drowning, and ask the God to raise them from the sea as he was: harder and stronger.
The ironborn do not fear the bloodiest battle or the roughest waves, for the Drowned God taught them long ago that what is dead may never die. When an Ironborn falls, they say that the Drowned God needed a strong oarsman and took him down to feed in the God's watery halls, attended by mermaids.
But even in death an ironborn is a warrior. They fight against the Storm God, who holds a castle in the clouds and sends the winds to lure the ironborn off course or wreck their ships. It is said that the Grey King waged war against the Storm God for a thousand years. with the Drowned God's help, he slew the great Sea Dragon Nagga and used her bones for his hall. After his death, the Storm God tried to wash away any memory of this terrible foe, but his songs fill the ironborn's halls to this day.
It was the Storm God who first blew the Andals to the Iron Islands to subdue the Ironborn and turn them from their faith. They conquered and killed their king, but in time they forsook their septs for the shore and their fat Septons for the Drowned Men. The Andals came to them as conquerors, but in the end they drowned.
The ironborn are of the sea, as their god made them, and given to it as their god taught them. They do not fear the Storm God's winds or his waves. But others should, for they bring the ironborn to them.