The much-anticipated Game of Thrones prequel series, House of the Dragon, has finally soared onto our screens, introducing viewers to the ancestors of Daenerys Targaryen, who look set to wage a bloody war over the right to succession and to sit on the Iron Throne.


The heir apparent is Prince Daemon Targaryen (Matt Smith), the volatile and violent Commander of the City Watch and brother to King Viserys I Targaryen (Paddy Considine), who refuses to condemn his sibling's actions until it's too late, setting in motion a chain of events that will lead to a civil war.

The first episode of House of the Dragon, titled The Heirs of the Dragon, makes a number of references to something called Dark Sister, which will go on to play an important part in the looming conflict.

When Prince Daemon first arrives at court, he presents his niece Princess Rhaenyra (Milly Alcock) with a necklace – a piece of jewellery made, she notes, of Valyrian steel, "like Dark Sister".

Later, a despondent Daemon is encouraged by his lover and ally Mysaria (Sonoya Mizuno) to fight back against those who'd oppose his ascension to the throne. She reminds the prince that he is no ordinary warrior – he wields Dark Sister, which puts him a cut above (quite literally).

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But what exactly is Dark Sister, and why is it so important to the House of the Dragon mythology? Read on for a potted (or should that be pointed?) history.

What is Dark Sister in House of the Dragon?

To put it simply, Dark Sister is a sword – but a very special sword. Forged from Valyrian steel, it holds a keen edge that remains sharp forever without the need for honing.

Though its exact origins are unclear, Dark Sister is believed to have been in the possession of House Targaryen since before Aegon's Conquest – a campaign throughout which Aegon I Targaryen and his dragons conquered most of Westeros, assuming rule over six of the Seven Kingdoms (bar Dorne, which successfully resisted).

While Aegon wielded Blackfyre, another treasured ancestral blade of House Targaryen, Dark Sister was used most frequently by – appropriately enough – his sister, Queen Visenya. The longsword was later bestowed on her 13-year-old son, Prince Maegor Targaryen – though Maegor was later given Blackfyre to wield in battle, with Dark Sister hanging on the walls of his chambers on Dragonstone, the original seat of House Targaryen in Westeros.

Dark Sister was later stolen by Queen Alyssa Velaryon, widow to Maegor's brother King Aenys I, when she fled Dragonstone along with her son Jaehaerys and daughter Alysanne, with Jaehaerys later inheriting the sword and becoming King following the demise of Maegor (who'd himself inherited the Iron Throne following his brother's death).

The weapon was then passed to one of King Jaehaerys's sons, Prince Baelon Targaryen, who used the sword to slay Myrish exiles responsible for the death of his brother, Prince Aemon.

Matt Smith in House of the Dragon.
Matt Smith as Daemon Targaryen in House of the Dragon. Sky/HBO

As established in The Heirs of the Dragon, Prince Baelon also perished, leaving King Jaehaerys without an obvious heir. Though 14 succession claims were heard by a Great Council, the two frontrunners were Princess Rhaenys Targaryen (Eve Best), and her cousin Prince Viserys Targaryen (Paddy Considine).

Rhaenys was the King's eldest descendent, but Viserys was his eldest male descendent and was picked over his cousin to rule, earning Rhaenys the unfortunate nickname of the 'Queen Who Never Was'.

Viserys inherited the Iron Throne, but it was his brother Daemon who was gifted Dark Sister by Jaehaerys for his prowess in battle.

Daemon is seen to use the sword in his bout with Ser Criston Cole (Fabien Frankel) at the King's tourney in The Heirs of the Dragon, though on this occasion he finds himself bested by the Dornish newcomer.

Did Dark Sister appear in Game of Thrones?

Maisie Williams as Arya Stark in Game of Thrones
Maisie Williams as Arya Stark in Game of Thrones. HBO

No, Daemon's weapon never makes a physical appearance in Game of Thrones, having been lost in the intervening years between House of the Dragon and the original series.

Dark Sister is referenced, however, in season 2, episode 7, A Man Without Honour, when Arya Stark (Maisie Williams) – posing as a servant – interrupts Tywin Lannister (Charles Dance) as he reflects on how Aegon Targaryen "changed the rules" by unleashing dragons in combat.

"Aegon and his sisters," Arya corrects Tywin. "It wasn't just Aegon riding his dragon. It was Rhaenys and Visenya, too."

She continues: "Visenya Targaryen was a great warrior. She had a Valyrian steel sword she called Dark Sister."

So there you have it, the sword of legend, now seen in action in House of the Dragon – and doubtless Daemon will use the weapon to wreak havoc on King's Landing and beyond, now that his right to replace his brother on the Iron Throne has been rescinded.

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House of the Dragon is available exclusively on Sky Atlantic and streaming service NOW.

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