Dark Sister
From A Wiki of Ice and Fire
Dark Sister is a famous Valyrian steel longsword, one of two ancestral swords of House Targaryen (the other being Blackfyre). Dark Sister is last known to have been wielded by Bloodraven.
History
The sword was in the possession of the Targaryen since before the War of Conquest and probably passed down the line by inheritance. It was known to be wielded by Visenya, Aegons elder sister and wife, Prince Aemon the Dragonknight and Lord Bloodraven. [1] It is unknown whether Bloodraven was allowed to take the sword with him when he was sent to the Night’s Watch. Its current whereabouts have as yet not been revealed.