Mjollnir

)   Mjollnir   (No tile)
Base item	war hammer
Damage vs. small	1d4+1 +1d24
Damage vs. large	1d4 +1d24
To-hit bonus	+1d5
Bonus versus	non-shock resistant
Weapon skill	hammer
Size	one-handed
Affiliation	neutral (Valkyrie)
When carried	(none)
When wielded	can be thrown at 25 strength (returns on 99100 of throws for Valkyries) lightning strikes targets on hit
When invoked	(none)
Base price	4000 zm
Weight	50
Material	iron

Mjollnir (colloquially known as Mojo) is an artifact that appears in NetHack. Its default alignment is neutral, and its base item is a war hammer.

One possible message for a T-shirt reads "Is that Mjollnir in your pocket or are you just happy to see me?"

Generation

A war hammer randomly generated on the ground or as a death drop has a base ¹⁄₂₀ chance of being made into an artifact, which has a ¹⁄₂ chance of being made into Mjollnir (and will otherwise be made into Ogresmasher), assuming no artifacts have yet been generated.

Mjollnir is the guaranteed first sacrifice gift for Valkyries, and lawful heroes may receive it as a sacrifice gift for a sacrifice with a value of 8 or higher—Mjollnir will not have anything added to its enchantment when randomly generated or given as a sacrifice gift.

Player monsters on the Astral Plane that generate with a war hammer have a ¹⁄₂ chance of that hammer being turned into a compatible artifact, which then has a ¹⁄₂ chance of being made into Mjollnir (effectively ¹⁄₄ if no artifact war hammers have been generated).

Description

While wielded, Mjollnir has +d5 to-hit and deals +d24 shock damage against monsters without shock resistance, with a ¹⁄₅ chance per item of destroying each wand and ring in the target's inventory and inflicting additional damage. Mjollnir's lightning strikes will also wake monsters in a fairly wide range around them. As a war hammer, Mjollnir gains a +2 to-hit bonus when thrown, and a hero can wield Mjollnir to shatter iron bars with a chance dependent on the hero's strength, whether they throw the artifact or force-fight with it, and the artifact's own enchantment.

However, Mjollnir is magically heavy, which means that only a hero that has 25 strength (usually from worn gauntlets of power) and is wielding the non-cursed artifact can throw it, and it is impossible to move by kicking: Mjollnir travels up to six squares when thrown, which is roughly half the maximum distance of a normal thrown war hammer. For a Valkyrie, the thrown Mjollnir will return 99100 of the time, and if they are not confused, stunned, blind, hallucinating, or fumbling when it returns, they will catch it 99100 of the time. If a Valkyrie fails to catch the returning Mjollnir, it has an equal chance of falling at their feet or else striking them in the arm, with the shock damage possibly destroying wands and rings. Monsters will not ever throw Mjollnir while wielding it, regardless of their own strength.

If the hero is a Valkyrie wielding Mjollnir and their quiver is either empty or contains ammunition for a launcher, the fire command will prioritize throwing Mjollnir. The default autopickup settings will pick up Mjollnir without quivering the artifact if it fails to return after being thrown.

Strategy

The following information pertains to a recently-released stable version (NetHack 5.0.0) and will be subject to revision as strategy is developed and bugs are discovered and/or fixed.

Excalibur is not as easily accessible for lawful Valkyries as in NetHack 3.6.7, and the increased popularity of blue dragon scale mail and various additional means of guarding rings from shock damage makes throwing Mjollnir significantly less risky compared to previous versions.

Mjollnir is an excellent weapon for Valkyries of all alignments and neutral heroes such as Tourists and Clerics throughout much of the game. It can deal a lot of shock damage even with its low base weapon damage, and monsters with shock resistance are generally few and far between before the Castle: of those monsters, blue dragons and storm giants are quite rare, and tend to appear on very deep floors and in throne rooms; electric eels are similarly rare and appear only within swamps, certain Quest levels and some versions of Medusa's Island, and they can be killed by other forms of offense both ranged and otherwise or else evaded altogether; and brown puddings, black puddings and gelatinous cubes are not especially dangerous for a player that is not too low-leveled or careless.

This leaves energy vortices, shocking spheres and the humanoid angelic beings as the primary pre-Castle dangers and obstacles for a hero using Mjollnir as their main weapon. From the Castle itself to the depths of Gehennom, Mjollnir's damage output may begin to falter: storm giants and blue dragons become slightly more common, shock-resistant arch-liches are one of the biggest threats within Gehennom in general, and various other monsters such as green slimes, and hostile aligned priests (including the high priest of Moloch) also resist shock damage—green slimes and angelic beings can also be created via the summon nasties monster spell, and the Sanctum is full of hostile priests. During the ascension run, several hostile angelic beings and priests will be encountered on the Astral Plane alongside the Riders, which resist nearly all forms of elemental damage.

A hero that is performing two weapon combat with Mjollnir can shore up their damage using a suitably-strong offhand weapon, particularly against shock-resistant targets—heroes with Mjollnir as their primary weapon will similarly want a good secondary source of damage against those targets, whether through another strong melee weapon (including other artifacts) or a stack of projectiles such as daggers. One of Mjollnir's primary drawbacks is that it does not grant the hero shock resistance at all, requiring an actual source of the property or another form of defense against shocking spheres and energy vortices. Additionally, the wide range of damage of Mjollnir means that securing kills with the artifact can prove annoyingly unreliable at times, even before shock-resistant monsters start becoming more common in the later stages.

The ability to throw Mjollnir and have it return as a Valkyrie is a very attractive prospect, with minuscule odds of the thrown artifact either failing to return or else hitting the hero as it returns, but the fact that such chances exist at all are enough to put many players off the idea notion of throwing it. The chance of destroying rings and wands, whether they belong to hostile monsters or are in the hero's own inventory, also deters players who seek to preserve loot for similar reasons.

For Valkyrie players willing to build around throwing Mjollnir regardless, blue dragon scale mail or a ring of shock resistance are highly recommended if not mandatory: the gauntlets of power they need to wear will not protect the hero's worn rings from shock damage, but extrinsic sources of shock resistance will protect the hero's inventory from shock damage 99100 of the time. A stack of daggers or similar other projectiles can mitigate the possibility of the thrown Mjollnir failing to return by providing an option against weak or slow-moving monsters, with Mjollnir becoming a priority once the projectiles are exhausted or the hero urgently needs the extra damage. Beware when throwing Mjollnir at a disenchanter—artifacts have a ⁹⁄₁₀ chance of resisting the passive disenchantment, but disenchantment that occurs with a thrown Mjollnir will not produce a message as hitting a disenchanter in melee combat does.

Lawful Valkyries will consider Excalibur to be an equally-stellar if not superior weapon, with a damage bonus that applies to all monsters alongside a source of the rare drain resistance property and the relative lack of noise caused by using it in combat. However, Excalibur still allows monsters to track the hero and is also more difficult to obtain in comparison, with only a ¹⁄₃₀ chance of success when dipping a long sword into a fountain compared to ¹⁄₆ for a Knight—amassing maximum luck for the best odds of obtaining Excalibur by crowning will typically require a means of raising it outside of sacrifice at an altar (e.g. throwing identified gems to a white unicorn), paired with a luckstone or similar luck item.

Average damage calculation

The average damage calculations in the following table do not include bonuses from weapon skills, strength, or from using a blessed weapon against undead or demons.

Weapon	Shock resistant		Not shock resistant
	Small monster	Large monster	Small monster	Large monster
+0 Mjollnir	$\frac{1+4}{2}+1=\mathbf{𝟑}\mathbf{.}\mathbf{𝟓}$	$\frac{1+4}{2}=\mathbf{𝟐}\mathbf{.}\mathbf{𝟓}$	$\frac{1+4}{2}+1+\frac{1+24}{2}=\mathbf{𝟏}\mathbf{𝟔}$	$\frac{1+4}{2}+\frac{1+24}{2}=\mathbf{𝟏}\mathbf{𝟓}$
+7 Mjollnir	$\frac{1+4}{2}+1+7=\mathbf{𝟏}\mathbf{𝟎}\mathbf{.}\mathbf{𝟓}$	$\frac{1+4}{2}+7=\mathbf{𝟗}\mathbf{.}\mathbf{𝟓}$	$\frac{1+4}{2}+1+\frac{1+24}{2}+7=\mathbf{𝟐}\mathbf{𝟑}$	$\frac{1+4}{2}+\frac{1+24}{2}+7=\mathbf{𝟐}\mathbf{𝟐}$

History

Mjollnir is introduced in NetHack 3.0.3, where it replaces the artifact Thunderfist that was added in NetHack 3.0.0: Thunderfist was an artifact lucern hammer, which is a type of polearm that was most likely mistaken for a "standard" hammer weapon. Mjollnir's throwing requirements and special behavior for Valkyries are introduced in NetHack 3.1.0.

In versions up to NetHack 3.6.7, including some variants based on those versions, a neutral hero in a role without a guaranteed first sacrifice gift may be given Mjollnir as their first artifact gift (with Valkyries of any alignment always receiving Mjollnir as their first gift), and any neutral hero that is given a gift after their first may randomly receive Mjollnir. NetHack 5.0.0 reworks artifact balance and sacrifice gifts to their current behavior via commit d87cadaf and commit c2c797fa—it also adds the ability for a hero to break iron bars with a wielded war hammer via commit f61e1e8e.

Origin

Mjölnir (from Old Norse Mjǫllnir) is the hammer of the thunder god Thor in Norse mythology, used both as a devastating weapon and as a divine instrument to provide blessings. Thor and his hammer appear depicted on a variety of objects from archaeological record, including the runic Kvinneby amulet from the 11th century, and in numerous sources including the Poetic Edda and the Prose Edda of the the 13th century. One book of the Prose Edda, Gylfaginning, describes the god Thor and his "three special possessions", including Mjölnir and a pair of iron gloves called Járngreipr (Old Norse: "iron grip") that he must wear with his hammer—this is likely the basis for the strength requirement to throw the artifact weapon in NetHack, which can only be typically achieved via gauntlets of power.

Variants

Some NetHack variants may make significant adjustments to Mjollnir's abilities and functions.

SLASH'EM

In SLASH'EM, Mjollnir's base item is changed to a heavy hammer, which is made of metal rather than iron and has slightly higher base damage of 1d6 against all monsters—this change originated in NetHack Plus. As the heavy hammer is not randomly generated, Mjollnir can only be obtained through sacrifice, wishing or discovery in bones.

The changes to artifact weapon bonuses make Mjollnir far more formidable overall with flat +5 to-hit and +24 shock damage bonuses, and artifact weapons can also be wielded in off-hand during two weapon combat, making it an especially enticing off-hand candidate. However, Mjollnir still remains somewhat weak against shock-resistant monsters due to its base item's damage still being relatively low, and there are more troublesome shock-resistant monsters such as the electric bugs, the stronger golems, and the shoggoth and giant shoggoth.

A related set of changes is made to gauntlets of power in SLASH'EM: they set the hero's strength to 18/** when worn and augment it further based on the gauntlets' enchantment, meaning that they only grant 25 strength at +7 or higher—Valkyries are also granted the ability to safely enchant gauntlets of power from +5, making it much easier for them to obtain the required strength to throw Mjollnir compared to any other role.

Average damage calculation

The damage calculations below assume that the wielder of Mjollnir is a hero with Expert skill in hammer, which gives a +2 damage bonus. A blessed weapon deals 1d4 extra damage against demons and undead. The worst case scenario is against a shock-resistant, non-undead, non-demon monster. The best case scenario is against an undead monster or demon that is not shock-resistant.

Weapon	Against regular non-shock resistant monsters	Worst case scenario	Best case scenario
Uncursed Mjollnir + 0	$\frac{1+6}{2}+24+2=\mathbf{𝟐}\mathbf{𝟗}\mathbf{.}\mathbf{𝟓}$	$\frac{1+6}{2}+2=\mathbf{𝟓}\mathbf{.}\mathbf{𝟓}$	$\frac{1+6}{2}+24+2=\mathbf{𝟐}\mathbf{𝟗}\mathbf{.}\mathbf{𝟓}$
Blessed Mjollnir +7	$\frac{1+6}{2}+7+24+2=\mathbf{𝟑}\mathbf{𝟔}\mathbf{.}\mathbf{𝟓}$	$\frac{1+6}{2}+7+2=\mathbf{𝟏}\mathbf{𝟐}\mathbf{.}\mathbf{𝟓}$	$\frac{1+6}{2}+7+24+2+\frac{1+4}{2}=\mathbf{𝟑}\mathbf{𝟗}$

dNetHack

In dNetHack, notdNetHack and notnotdNetHack, Mjollnir is made stronger from improvements to the war hammer as a weapon, and appears as a lightning-bolt embossed war hammer when unidentified.

Mjollnir has +1d5 to-hit, deals 1d8+2d4+3 damage versus small monsters, and deals 1d8+2d4 damage versus large monsters, with a bonus of +1d24 shock damage against all non-resistant monsters. Mjollnir grants shock resistance and blindness resistance while wielded—it can be wielded in the off-hand by Valkyries performing two weapon combat, but is heavy enough with its default material that a medium-sized hero cannot do so without incurring a to-hit and damage penalty. Hitting with Mjollnir in melee randomly fires lightning bolts that deal 6d6 damage and blind monsters, and hitting a target with a thrown Mjollnir randomly creates 3x3 electric explosions that deal 6d6 damage and are centered on the target.

When the wielded Mjollnir is thrown by a Valkyrie hero or a player monster valkyrie wearing gauntlets of power, it will always return to the wielder's hand, and will always be caught successfully if the wielder is not impaired—however, it only has half the normal range a thrown projectile would normally have due to its weight (i.e. STR/4, or 6 squares), similar to how it is magically weighted in vanilla NetHack.

xNetHack

In xNetHack, war hammers are two-handed and deal 2d6 damage to small creatures and 2d8 to large creatures - this indirectly makes Mjollnir more powerful as an artifact, but also incompatible for twoweaponing or use with a shield.

Additionally, Mjollnir can be invoked to zap a lightning bolt in a selected direction as with the wand of lightning, dealing 8d6 damage to monsters that it hits.

SpliceHack

In SpliceHack and SpliceHack-Rewrite, Mjollnir can be invoked to fire a thunderbolt.

EvilHack

In EvilHack, Mjollnir provides shock resistance while wielded, and its base item is changed to a heavy war hammer, which deals d8+1 to small monsters and d10 to large monsters.

Priests of all alignments that are crowned will receive Mjollnir as their crowning gift, which is done in a manner similar to Excalibur: if you are a Priest wielding a heavy war hammer and Mjollnir has not yet been generated at the time of crowning, the hammer will be transformed into Mjollnir.

Mjollnir can be combined with Cleaver at a forge to create Tempest, an artifact halberd that retains Mjollnir's shock resistance and lightning attack.

SlashTHEM

In SlashTHEM, in addition to SLASH'EM details, all heavy war hammers are two-handed and made much stronger as a base item, dealing 2d8 damage to small monsters and 2d10 to large ones. This decreases Mjollnir's utility for some neutral playstyles that would rely on two weapon combat or access to the shield slot (e.g. for a shield of reflection), but the artifact is still a powerful source of damage.

Encyclopedia entry

Forged by the dwarves Eitri and Brokk, in response to Loki's challenge, Mjollnir is an indestructible war hammer. It has two magical properties: when thrown it always returned to Thor's hand; and it could be made to shrink in size until it could fit inside Thor's shirt. Its only flaw is that it has a short handle. The other gods judged Mjollnir the winner of the contest because, of all the treasures created, it alone had the power to protect them from the giants. As the legends surrounding Mjollnir grew, it began to take on the quality of "vigja", or consecration. Thor used it to consecrate births, weddings, and even to raise his goats from the dead. In the Norse mythologies Mjollnir is considered to represent Thor's governance over the entire cycle of life - fertility, birth, destruction, and resurrection.