The Hellholt is named after an incident where unfriendly visitors were locked in the great hall and burned to death. The castle is located near the source of the river Brimstone. It is said that half the Ullers are half-mad, and the other half are even worse. The only members of the house to appear are Lord Harmen Uller who is the current head and his brother Ser Ulwyck Uller. Lord Harmen is natural father to Ellaria Sand, Oberyn Martell’s paramour.