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Game of Thrones

Why do Valyrian steel and dragonglass kill White Walkers?

Moderate Confidence

They’re enchanted, fire/blood-aspected materials (“frozen fire” dragonglass and sorcerously forged Valyrian steel) that counter and unbind White Walkers’ cold magic; the Night King’s death further required a mirrored creation-spot strike.

Competing Theories

We've gathered the strongest arguments from across the internet. Here's how they stack up.

Fire-Against-Ice Magic

Best Supported

Lore explainers and wikis (synthesizing show canon) plus r/asoiaf meta

Dragonglass and Valyrian steel are imbued with fire/blood-aspected sorcery that inherently counters and unbinds the White Walkers’ cold magic.

  • Across the series, only dragonglass and Valyrian steel ever kill White Walkers, implying a shared magical property rather than mere sharpness or heat.
  • Direct on-screen kills: Sam’s dragonglass dagger and Jon’s Valyrian steel sword shatter Walkers, while ordinary steel fails.
  • Dragonglass is labeled “frozen fire,” and Valyrian steel is associated with dragonfire and lost spells, tying both to fire/blood sorcery.
  • Valyrian steel’s forging with dragonfire/spells is a persistent franchise throughline, supporting a sorcerous, not purely metallurgical, explanation.

Background Context

In Game of Thrones, only dragonglass and Valyrian steel can kill White Walkers, beings animated by ancient cold magic. Fans wonder why these materials work and why Arya's strike ended the Night King. This page explains the in-universe mechanics.

Full Analysis

A detailed breakdown of each theory with supporting evidence.

Core Claim

Dragonglass and Valyrian steel are imbued with fire/blood-aspected sorcery that inherently counters and unbinds the White Walkers’ cold magic.

On screen, only dragonglass and Valyrian steel ever destroy White Walkers; they don’t merely wound them, they unmake them into shards, while ordinary steel fails outright. The Citadel page explicitly calls dragonglass “frozen fire,” and franchise lore repeatedly links Valyrian steel to dragonfire and lost spells, signaling that both materials carry a fire-aspected, blood-forged enchantment. This cleanly explains why Jon’s Valyrian steel and Sam’s dragonglass behave identically against Walkers despite being different substances: both are vessels for a countervailing magic that unravels the Walkers’ cold enchantment at the moment of contact. The visual language reinforces this: normal steel shatters when meeting a Walker’s magic, but dragonglass and Valyrian steel make Walkers explode into icy fragments, as if a hostile enchantment is being dispelled. The creation of the Night King via a dragonglass blade at a weirwood further situates the Walkers as creatures of deep, elemental magic—so it is coherent that inverse, fire/blood sorcery baked into “frozen fire” and sorcerous steel would be their specific bane. Even the Night King’s resilience to mundane heat is compatible: it’s not generic fire that undoes them, but fire-bound magic precisely anchored in these artifacts.

Core Claim

The same magic that created the Night King can unmake him and his kind, requiring a strike with creation-linked material to the original creation site.

The show depicts the Night King’s origin: a dragonglass blade pressed into a captive’s chest at a weirwood transforms him, establishing a precise locus and material of creation. Arya later ends him with a Valyrian steel dagger thrust to that same chest spot, and the visual echo between the two scenes is unmistakable; immediately, all other Walkers and their wights disintegrate. The showrunners then confirm the intent: Arya had to hit the exact place the dragonglass was placed, with Valyrian steel, to uncreate him. This symmetry accounts for the franchise’s network effects: killing a Walker collapses the wights it sired, and killing their progenitor collapses the entire army. It also reconciles earlier observations: dragonglass kills lesser Walkers because it is the raw creation material, while Valyrian steel—sharing the requisite enchantment profile—can perform the same unmaking. Dragonfire failing where a precise enchanted strike succeeds follows naturally if the spell that binds the Night King requires a mirrored, keyed disruption rather than brute force.

Core Claim

Valyrian steel’s ability to kill White Walkers derives from dragonglass or its fire-aspected essence being incorporated or replicated in the steel’s sorcerous forging.

Only two materials kill Walkers: dragonglass and Valyrian steel. The simplest unifying hypothesis is a shared essence or process—either literal obsidian admixture or an equivalent effect achieved through dragonfire and spells in Valyrian metallurgy. The Citadel page calling dragonglass “frozen fire,” combined with long-standing lore that Valyrian steel is forged with dragonfire and sorcery, points to a common fire-aspected signature. On screen, both materials make Walkers explosively disintegrate, while common steel cannot even withstand contact with their magic, supporting a qualitative, not merely mechanical, difference. Under this model, Valyrian steel is “armored dragonglass”: the same anti-Walker property stabilized in a durable blade, marrying the killing essence of obsidian to a resilient matrix—hence its parity with raw dragonglass in effect but superiority in battlefield practicality.

Core Claim

White Walkers, like fae in folklore, are resistant to mundane alloys but vulnerable to ‘true’ or magically wrought iron, with Valyrian steel embodying that potent form.

Folklore repeatedly frames cold spirits and fae as vulnerable to ‘cold iron,’ a special or purer form of iron that pierces their enchantments where common metal fails. On screen, ordinary steel shatters against a Walker’s magic while Valyrian steel endures and destroys them, echoing the folklore’s material hierarchy: only metal of the “right” purity or numinous forging can bite the otherworldly. In this reading, Valyrian steel is the show’s ‘true iron’—an iron perfected by sorcery to regain the primordial potency mundane steel lacks. Dragonglass then occupies a parallel folkloric niche: a pre-human, volcanic substance aligned with elder powers that similarly bypasses Walker protections. While not iron, it belongs to the same category of primal, enchantment-breaking substances in mythic logic, providing an in-universe rationale for why two very different materials share an outcome against the fae-like Walkers.

The Verdict

Moderate Confidence

Best Supported Theory

Fire-Against-Ice Magic

How We Weighed the Evidence

I prioritized on-screen outcomes showing what does and does not kill White Walkers (Sam’s dragonglass dagger; Jon’s Valyrian steel; ordinary steel failing/shattering). Those are decisive for the fact pattern. Next in weight were official HBO materials (e.g., Viewer's Guide/Histories & Lore) that label dragonglass as “frozen fire” and tie Valyrian steel to dragonfire and lost spells, since they speak directly to mechanism. Creator/showrunner commentary was applied narrowly where it clarified intent behind a specific event (the Night King’s kill conditions), but not to override absent on-screen exposition about general Walker vulnerability. Internal logic filled gaps only where it cleanly extended established evidence without contradicting it.

Our Conclusion

Best-supported answer: Valyrian steel and dragonglass kill White Walkers because they carry a fire/blood-aspected enchantment that counters and unbinds the Walkers’ cold magic (Fire-Against-Ice Magic). This matches every on-screen kill and is backed by official materials describing dragonglass as “frozen fire” and Valyrian steel as forged with dragonfire and spells. For the Night King specifically, a mirror-of-creation rule refines the picture: a keyed strike to the creation site with an appropriate enchanted material (Valyrian steel) unmade him and collapsed his network (Mirror-of-Creation Unmaking). Thus, the general vulnerability is fire-aspected enchantment; the Night King’s demise adds a positional, creation-linked requirement. Because the show never states the mechanism in dialogue, some inference remains, but the combined evidence makes Theory 1 the primary explanation, with Theory 2 explaining the Night King’s special case.

What Would Change This?

This verdict could change with additional canonical evidence, creator statements, or if a compelling new interpretation emerged that better fits the established lore.

Sources (12)

  1. 1
    Season 3, Episode 8 'Second Sons' (forest hut scene)Canon
  2. 2
    Season 5, Episode 8 'Hardhome' (interior hut fight)Canon
  3. 3
    Season 5, Episode 8 'Hardhome' (yard fight)Canon
  4. 4
    Season 6, Episode 5 'The Door' (Bran’s vision)Canon
  5. 5
    Season 7, Episode 6 'Beyond the Wall' (Walker destroyed; wights fall)Canon