A moratorium is in effect on adding information from Fire and Blood until December 20th.
Queen Visenya Targaryen was skilled in the use of Dark Sister, having trained beside her younger brother, King Aegon I Targaryen, since childhood. During the First Dornish War, the Targaryens were attacked on multiple occasions by assassins sent by Dorne, and Visenya possibly saved the king's life with Dark Sister in 10 AC in King's Landing. Two of Visenya's guards were killed during one attack, but Visenya slew the last assassin with her Valyrian steel blade. Aegon still felt he was sufficiently protected by his guards, but Visenya quickly drew Dark Sister and cut Aegon's cheek before the king's defenders could react. Aegon then entrusted Visenya with establishing the Kingsguard as more competent bodyguards.
Visenya bestowed Dark Sister on her thirteen-year-old son, Prince Maegor Targaryen, in 25 AC. Maegor wielded Blackfyre, however, after he became king with the death of his elder brother, King Aenys I Targaryen, in 42 AC. After Visenya died in 44 AC, the hostage Dowager Queen Alyssa Velaryon, Aenys's widow, fled from Dragonstone with her children Jaehaerys and Alysanne, taking Dark Sister from Visenya's chamber as well. King Maegor the Cruel had her son, Prince Viserys Targaryen, tortured to death in a failed attempt to locate Alyssa's whereabouts. In 48 AC, Jaehaerys carried Dark Sister when his claim to the Iron Throne was announced at Storm's End by Lord Rogar Baratheon.
Prince Daemon Targaryen was knighted at sixteen, and King Jaehaerys I gave him Dark Sister for his prowess. Ser Criston Cole defeated Daemon in the tourney for King Viserys I's accession, knocking Dark Sister from the prince's hand with a morningstar. Daemon wielded Dark Sister during his war for the Stepstones, using it to behead Craghas Drahar in 108 AC, and he also defeated a Braavosi exile with the blade during a duel for the hand of Laena Velaryon in 115 AC. During the Dance of the Dragons, in the Battle Above the Gods Eye, Daemon leapt from the back of his dragon, Caraxes, to plunge Dark Sister into the eye of Prince Aemond Targaryen. When Aemond's bones were found some years later in the waters of the Gods Eye, Dark Sister was thrust hilt-deep through his eye socket.
Lord Brynden Rivers bore Dark Sister, though his favorite weapon was a weirwood longbow. According to a semi-canon source, Brynden took Dark Sister with him when he went to the Wall to join the Night's Watch. The sword's current whereabouts are unknown.
Dark Sister was made for nobler tasks than slaughtering sheep. She has a thirst for blood.
- The World of Ice & Fire, The Reign of the Dragons: The Conquest.
- So Spake Martin: More Targaryen Descriptions (December 24, 2005)
- The World of Ice & Fire, Dorne: Dorne Against the Dragons.
- The World of Ice & Fire, The Targaryen Kings: Aegon I.
- The Sons of the Dragon.
- The World of Ice & Fire, The Targaryen Kings: Maegor I.
- The World of Ice & Fire, The Targaryen Kings: Viserys I.
- The Rogue Prince.
- The Princess and the Queen.
- The World of Ice & Fire, The Targaryen Kings: Viserys II.
- The Sworn Sword.
- /r/asoiaf: GRRM confirms long-held theory about Dark Sister, August 15, 2018