Home to the wealthiest of the great houses, the keep at Casterly Rock sits literally on top of a gold mine, built into the very rock. From that lofty yet uncomfortable position, House Lannister rules over the Westerlands (and influences all of Westeros, by virtue of the kingdom’s purse strings). With the ascension of Lord Tywin to the house seat, the Lords of the Rock developed a reputation for ruthlessness as well as riches. This was due in part to Tywin’s remorseless efforts to keep his bannerhouses in line, but also because Aerys II was murdered by one of his own Kingsguard: Ser Jaime Lannister. Their unofficial motto states, "A Lannister always pays his debts."