House Bolton of the Dreadfort is an ancient northern house sworn to Winterfell. The Red Kings of the Dreadfort warred against the Kings of Winter for thousands of years before they were finally brought to heel; the songs the smallfolk still sing of those wars are not pleasant ones. Their custom was to flay the skins of their fallen Stark enemies and hang them in the cellars of the Dreadfort, where it is whispered some hang still.
Bolton lords have bent the knee for longer than they ever held it free, but the old habits have never fully died. Lord Roose Bolton is a pale-eyed man of few words and fewer scruples, and his bastard son Ramsay is no better. The flayed man still flies above the Dreadfort.