Warning: This article contains spoilers from House of the Dragon episode 9.

In the world of Westeros, especially during the time of HBO's House of the Dragon, Valyrian steel is a coveted metal, simply because no one alive can forge new ones. It's an element made with magic and spells in the land of Old Valyria, once the home of House Targaryen and House Velaryon before the empire's doom. The loss of Valyria brought the loss of the knowledge to make more Valyrian steel objects.

As House of the Dragon series co-creator and co-showrunner Ryan Condal says, "It's a technology that doesn't exist anymore. Their blades are not made anew. So all the Valyrian steel is a fixed number of assets in the world. Even in a time when Targaryens are in power, they themselves as Targaryens are not able to make Valyrian steel. So they're going to take care of it."

Three Valyrian steel blades are featured in House of the Dragon's first season: Blackfyre, the sword wielded by King Viserys I Targaryen (Paddy Considine); Dark Sister, the sword of Prince Daemon Targaryen (Matt Smith); and the dagger that has been commonly referred to as the catspaw dagger. Peter Johnson, a Swedish sword maker, crafted the first two blades, according to Tim Lewis, the show's master armorer who spoke with EW about the making of these Westerosi relics.

"Ryan was so keen to have these amazing swords… It kind of influenced the way I took the rest of the sword designs, really," Lewis says. "Hopefully they all tie together."

Blackfyre and Dark Sister

House of the Dragon

Paddy Considine and Matt Smith as King Viserys and Daemon Targaryen

| Credit: Ollie Upton/HBO

Each piece of Valyrian steel comes with its own history. Blackfyre, one of two ancestral blades of House Targaryen, was in the possession of Aegon I Targaryen, known as Aegon the Conqueror for his conquering of Westeros. It's the blade that would provide the name for House Blackfyre, a branch of House Targaryen whose sigil was a black tri-headed dragon breathing black flames against a red backdrop.

Upon his death, Aegon was burned in a funeral pyre with his hands around Blackfyre, but his younger son, Maegor Targaryen, would later retrieve the blade. This made Blackfyre darker in color than other Valyrian steel pieces.

The sword passed from ruler to ruler, including King Jaehaerys I Targaryen, seen in the opening of House of the Dragon by actor Michael Carter. Upon his death, the sword passed to King Viserys and then to King Aegon II Targaryen (Tom Glynn-Carney), who, on direction from his mother Queen Alicent Hightower (Olivia Cooke) and grandfather Otto Hightower (Rhys Ifans), usurped the throne from Viserys' chosen heir, Rhaenyra Targaryen (Emma D'Arcy). Blackfyre, along with Viserys' dagger, were used in Aegon's coronation as heirlooms to bolster his claim to the Iron Throne.

Lewis and Johnson had basic descriptions from Condal to go off for the design. Blackfyre is "a kingly statement piece," Lewis says. "And then, going into all the detailing, Peter just had literally cast the pommels in silver. We could never, we would never do anything like that on a film. All the detailed work that he did was just so intricate and beautiful."

House of the Dragon

Matt Smith stars as Prince Daemon Targaryen in 'House of the Dragon.'

| Credit: Ollie Upton/HBO

The same goes for Dark Sister, the other Targaryen ancestral blade that goes back to the days of Aegon. This sword has been with House Targaryen since before Aegon's Conquest. It's more "slender" than Blackfyre, Lewis describes. Queen Visenya Targaryen, the older sister of Aegon the Conqueror, was a notable wielder of Dark Sister. Daemon now brandishes the blade in House of the Dragon, which was bestowed on him by King Jaehaerys for his prowess.

"I'm very much of a style of manufacture, which is authentic, as well. And that's the same as Peter," Lewis explains. "It didn't want to feel like a fantasy sword. It wanted to feel like an authentic sword and how an authentic sword would've been made. It would've been cast in wax and then cast as a lost wax cast, and then the wooden handle would be made up and wrapped in leather and all these components would come together on the blade. That's how we make our swords."

One general note Lewis remembers hearing from Condal and season 1 co-showrunner Miguel Sapochnik: "There are dragons in this world, but you have to believe that there are dragons in this world by believing that everything else within the world was authentic."

Unlike other swords in House of the Dragon, Johnson used actual Damascus steel to make Blackfyre and Dark Sister. "You don't want anything that's too fantastical," he adds. "The only thing that's fantastical is these dragons. That was their feel on it. So I was trying very hard to keep everything historically accurate as possible, but playing with design."

Viserys' dagger (a.k.a. the catspaw dagger)

House of the Dragon Episode 9

Aegon II Targaryen (Tom Glynn-Carney) wields his father's Valyrian steel dagger for the coronation on 'House of the Dragon.'

| Credit: Ollie Upton / HBO

The history of the Valyrian steel dagger in Viserys' possession is written on the blade itself.

The exact origins are unknown, but we do know the dagger was once in possession of Aenar Targaryen, a dragonlord of Old Valyria whose daughter Daenys the Dreamer foresaw the Doom of Valyria. The dagger then passed to Aegon the Conqueror, who had the Valyrian pyromancers carve in High Valyrian a prophecy he dreamt that he dubbed "A Song of Ice and Fire," which predicted the rise of the white walkers in Westeros during Game of Thrones and the Targaryen "prince that was promised" that could save humankind.

Game of Thrones sees this dagger first used by a catspaw assassin to try to kill Brandon Stark (Isaac Hempstead Wright) and again later by Arya Stark (Maisie Williams) to destroy the Night King and end the Great War against the army of the dead.

Early on in the pre-production of House of the Dragon, Condal and Sapochnik were keen to make Viserys' dagger the same catspaw dagger. "We got the catspaw dagger over from Ireland, from the Legacy [tour]," Lewis recalls. "We had it there and we took measurements and we were allowed it for a couple of weeks. It's heavily guarded, came over in a case, and I kept it locked up whilst it was with us. We looked at it and we said, 'Well, maybe we could just adjust it here. We don't want it to feel like it's directly the same thing.' And also Paddy had to wear it all the time. It was always on him, and that was what he wanted to do, as well. He was really key. That was partly one of his ways of defining his character: it was always on him."

Ultimately, the armory decided to craft a new prop. Lewis says they reduced the length so Considine could always wear it on him as Viserys, while giving the effect of a dragonbone handle and the detailed metalwork. "There is a gem on there, which again goes into the Game of Thrones version of it," he notes. "But we just thought the metalwork and that [gem] could be something that could be altered or damaged. We wanted to feel like you could take the blade, you could take the handle, you could change the metalwork a bit, and it becomes that one from Game of Thrones."

House of The Dragon the catspaw dagger with Aegon the Conqueror's Ice and Fire prophecy

Aegon the Conqueror's prophesy is carved into Viserys' Valyrian steel dagger.

| Credit: HBO

Unlike the Blackfyre and Dark Sister props, Lewis and his team used aluminum to make the dagger. It's a lighter material and easier to work with, but it meant etching all of the same Damascus details into the blade for the same Valyrian steel effect. That made the dagger "the most arduous of blades to make in the whole of Westeros," Lewis remarks.

"We would first come up with the design, then we would draw that up on a computer, cut that out on a vinyl, lay the vinyl onto the blade, peel off each tiny little bit of lowlight of the blade, and that would then get etched in an acid, and then you would take that out. It took ages to do one blade. You're just pulling all these vinyls off, and it's not until you finally take it out of the acid and clean it up and then you pull all the rest of the vinyl off to know if it's worked. And if it hasn't worked, you've wasted the entire time you've spent making the blade and then trying to etch it."

Fortunately for the sake of Lewis' sanity, his team did not have to etch in all the High Valyrian glyphs on the dagger that shows up in the context of House of the Dragon when it's heated by fire. That was special effects. But they did have to supply a knife that could be placed in fire for the shoot. "The knife that we actually made would not survive going in that fire originally because the handle itself is a form of plastic," Lewis says. "So that knife you see in [episode 4] is actually a plaster version, which we worked up. And then visual effects take over."

Subscribe to EW's West of Westeros podcast, which goes behind the making of House of the Dragon and the growing Game of Thrones universe.

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