Seat of House Dondarrion in the Dornish Marches, a stout castle of black basalt guarding the Boneway where it descends from the red mountains. With Nightsong and Stonehelm it forms the old shield of the stormlands against Dorne.
The Forked Lightning
The songs tell of the first Dondarrion, a messenger riding through a storm-black night with word for the Storm King, beset by two Dornishmen upon the road. A bolt of purple lightning split the sky and struck his foes down, and in thanks he took for his banner a forked purple bolt on black, strewn with four-pointed stars. That sigil has flown over Blackhaven ever since.