The Flayed Man of House Bolton
House Bolton is a minor house of the North, originally sworn to House Stark. Their sigil is a flayed man, as the Boltons are infamous for flaying their enemies.
A thousand years ago, the Boltons rebelled against the King in the North, but their uprising was put down by Karlon Stark, who was rewarded with his own lands, where he built the Karhold.
It is currently led by Roose Bolton, a cold lord, and his bastard son, Ramsay Bolton. Roose Bolton was present and aided the Freys in their slaughter of Catelyn and Robb Stark at the Red Wedding, Roose Bolton also freed Jaime Lannister from the clutches of the Bloody Mummers. As of A Dance with Dragons, the Boltons are sworn to the Iron Throne but continue to move of their own accord, in their own interest.