Item from House of the Dragon by George R.R. Martin
A Valyrian steel longsword, thinner and lighter than Blackfyre, wielded by Daemon Targaryen. The blade he drove through Aemond's eye above the Gods Eye.
Dark Sister is a Valyrian steel longsword, narrower and lighter than its sibling Blackfyre — designed for a quicker, more agile fighting style. Originally wielded by Visenya Targaryen, Aegon the Conqueror's warrior-queen, the blade passed through generations of Targaryens before reaching Daemon. In Daemon's hands, Dark Sister becomes one of the most feared weapons in Westeros. He carries it through the Stepstones campaign, through his years of scheming and fighting, and finally into his last act — leaping from Caraxes onto Vhagar above the Gods Eye to drive Dark Sister through Aemond's remaining eye. The sword sinks with them into the lake. Whether it was ever recovered is a matter of legend.
Valyrian steel longsword, thinner and lighter than Blackfyre. Wielded by Visenya Targaryen and later Daemon Targaryen. Dark steel with a distinctive narrow blade. Made for speed.
Also known as: Daemon's sword, Visenya's sword