White Walkers Have A Huge Weakness - But Only Real Game Of Thrones Fans Know It

Throughout the run of "Game of Thrones," characters like Cersei Lannister (Lena Headey) and Daenerys Targaryen (Emilia Clarke) fought amongst themselves over the right to sit upon the Iron Throne of Westeros and control the Seven Kingdoms. What they all ignored, though, was the constant looming threat coming from the North, beyond the Seven Kingdoms proper ... the White Walkers and their army of wights, an enormous mass of undead victims who rise time and time again, no matter how many times they're "killed."

If you've seen the series from beginning to end, you know that White Walkers — the more powerful entities, as wights are essentially just corpses reanimated by the Walkers — only have a few weaknesses which are far and few between (more on those in just a moment). If you've read George R.R. Martin's original books, though, you know that White Walkers, much like vampires of lore, also stay hidden during the day and only emerge at night (in fact, they really only appear in the dead of night). Obviously, this isn't the case on the show; in the Season 2 finale "Valar Morghulis," Samwell Tarly (John Bradley) is horrified when, while traveling beyond the Wall, he sees a massive army of White Walkers and wights alike assembling in broad daylight. 

It feels like this change was probably made to make sure that every single White Walker sequence wasn't interminably dark (though the series never shied away from things like that in later seasons), but let's discuss the weaknesses of the White Walkers for a moment. Besides the fact that they fear daylight in the novels, what else can defeat them — and why are they such legendary villains?

Why are White Walkers so scary, and how can someone defeat them?

The White Walkers are definitely terrifying villains no matter what; they're silent, undead, and ancient beings who have the power to create vast armies with the raise of an arm (in the Season 5 episode "Hardhome," we witness the Night King do just that after a massive battle between the White Walkers, wildlings, and men of the Night's Watch). Though the Wall is meant to separate them from the population of the Seven Kingdoms — and has done so for years — in "Game of Thrones," we witness the White Walkers gain enough power to bring down a portion of the wall, which is aided by the wight dragon they're able to create after killing Viserion, one of Daenerys' beloved dragons. So how can they be defeated?

Two known substances in "Game of Thrones" can destroy a White Walker once and for all — Valyrian steel and dragonglass. (Normal wights can be destroyed with fire, thankfully). We only see a few people actually defeat White Walkers with either of those materials, as Valyrian steel (from the ancient land of Valyria) is exceedingly rare and used to make swords, whereas dragonglass is a mysterious resource not found in many places across Westeros. In the Season 3 episode "Second Sons," Sam Tarly successfully kills a White Walker with a dragonglass dagger, and in the Season 6 episode "The Door," Meera Reed (Ellie Kendrick) uses a spear topped with the same material while battling a horde. The heroic Jon Snow (Kit Harington), who has the most interactions with the White Walkers, kills two with his Valyrian steel sword Longclaw. So who takes down the Night King in the end?

Here's how one character destroys every single White Walker in one fell swoop — and why that stinks

In the end, during the Season 8 episode "The Long Night," it's Maisie Williams' Arya Stark who does the deed and takes down the ancient and powerful Night King once and for all, which (helpfully) decimates his entire army of lower-ranking White Walkers and wights in the process. But let's back up a moment — how does this even come to pass?

During the long-awaited Battle of Winterfell, Jon Snow is in the thick of the fight throughout the entire ordeal as White Walkers storm the Northern stronghold and the show's remaining heroes try to hold them off. As Daenerys swoops around on dragonback trying to incinerate the undead army, Viserion is fighting back alongside the Night King, and as Jon tries to get closer to his nemesis, his "sister" Arya is quietly making her way through the battle as well. See, Arya is trained as a silent, faceless assassin, and as it happens, she's armed with a Valyrian steel dagger; when she reaches the Night King, he strangles her for a terrifying moment before she quickly switches the dagger to her other hand and kills him. After that, the White Walkers simply vanish.

Should Jon Snow have been the one to kill the Night King based on his overall throughline? Yeah, probably. Is the scene where Arya does it really cool? Yeah, definitely. When all is said and done, the White Walkers are tough to defeat but cease to be a problem after Arya's attack ... though it should be noted that, per the book's canon regarding the White Walkers and daylight, the battle does take place in the dead of night.