As a medieval-style fantasy, Game of Thrones' creator George R.R. Martin borrowed from J.R.R. Tolkien's tradition of having specialized weapons complete with names and special, even magical, properties. Much of Game of Thrones' appeal lies in the complex characters and intricate political drama of Westeros, but it is still a show that prominently features dragons, ice zombies, and faceless assassins. To battle such threats, ordinary mortals need weapons, and some of those weapons are truly unique.
Among the rarest and most prized weapons in Game of Thrones are blades made of Valyrian steel, which is stronger than regular steel with edges that need never be sharpened. The secret of how to forge Valyrian steel was lost in the Doom of Old Valyria, a catastrophic event on the continent of Essos that occurred four centuries before the events of Game of Thrones. As such, only a scant few people in the known world have knowledge of the process of how to forge Valyrian steel weapons. The show has highlighted a small number of these weapons, most of which were centuries-old heirlooms passed down in high-born families across generations.
Along with Dragonglass (obsidian), Valyrian steel is one of the few substances that can kill White Walkers. However, this isn't widely known, as most people on Westeros still believe the Army of the Dead is just a myth. And even so, there are so few Valyrian steel weapons in existence. The following are the known weapons made of Valyrian steel we've seen on the show.
No single weapon has had a greater impact on Game of Thrones. The dagger, which has a Valyrian steel blade decorated in dragonglass and a hilt made of dragonbone, first appeared in season 1. It was given to a cutthroat assassin as the weapon intended to murder Brandon Stark, an assassination attempt foiled by Catelyn Stark and Summer the Direwolf. Catelyn brought the dagger to King's Landing, where Lord Petyr Baelish AKA Littlefinger identified it as his dagger, which he claimed he lost in a bet to Tyrion Lannister (in order to frame Tyrion as the mastermind of Bran's attempted murder). The dagger was later sighted in Ned Stark's chambers in the Hand of the King's office, and Littlefinger must have taken back possession of it after he betrayed Ned to the Lannisters.
The dagger wasn't seen again until season 7. First, a drawing of it appears in a book Samwell Tarly is reading when he researches Dragonglass in the Citadel at Oldtown. In the fourth episode, 'The Spoils of War,' Littlefinger gives the dagger to Bran Stark as an ironic gift. Bran then gave the dagger to his sister Arya, who had recently returned to Winterfell to reunite with her surviving siblings. The weapon once meant to kill a Stark is now ironically a Stark family heirloom. In the capable and dangerous hands of Arya, an assassin trained by the Faceless Men of Braavos, what further purpose the dagger will serve remains to be seen.
Ice was the huge ancestral greatsword of the Stark dynasty. Fittingly, its scabbard was made from the pelt of a wolf. In the two decades of peace since Robert Baratheon became King, Ice was used as more of a ceremonial weapon, swung by Ned Stark to behead traitors to the North. Ned brought Ice with him to King's Landing when he became the Hand of the King. When Robert was killed by a boar and the power struggle over the Iron Throne between Ned and the Lannisters took place, the Lannisters took possession of Ice when Ned was betrayed and imprisoned as a traitor. It was Ice used to behead Ned; it was swung by Ser Illyn Payne, the royal executioner. Finally, Tywin Lannister had Ice melted down and reforged into two different swords.