House Sunderland of the Three Sisters rules the Three Sisters, three islands located in the Bite. They reside in Sisterton.
Queen Marla "The Merciless" Sunderland
Queen Marla Sunderland, the first Pirate Queen of the Sisters and also the most ruthless and ambitious Pirate in her realm. She refused to accept a non-aggression pact with the Vale of Arryn, because they refused to pay her to keep her raiders of their coasts.
When the Vale of Arryn attacked the Mountain Clansmen, she was offered gold and riches if she joined the Mountain Clansmen against the andal invaders, which she gladly accepted and sent a raiding party to start raiding their coast.
While the Mountain Clansmen and the Andals clashed, Queen Marla set sail to Andaltown and completly looted the town. During her raiding, she encountered the Lord of Runestone with his valyrian steel sword, lamentation. She forced him to surrender the sword or be killed for it, which he surrendered. She then set sail to Pentos and started looting the city.
She never sent any forces to battle with the Mountain Clansmen, because she knew that they didn't need her forces.
Shortly after she raided Andaltown, she formed a coalition with the Pirate Kings of the Stepstones to co-operate their raiding attacks.