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	throwable lightning strikes on hit
When invoked	(none)
Base price	4000 zm
Weight	50
Material	iron

Mjollnir (colloquially known as Mojo) is an artifact weapon that appears in NetHack. It is neutral-aligned, 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 randomly generated war hammer has a base ¹⁄₂₀ chance of being made into an artifact, which has a ¹⁄₂ chance of being Mjollnir (and otherwise being Ogresmasher) if no artifacts have already been generated. It is the first guaranteed sacrifice gift for Valkyries, and neutral characters may receive Mjollnir 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 that is not yet generated, resulting in a ¹⁄₄ chance of the war hammer becoming Mjollnir if neither it or Ogresmasher are generated.

Description

Mjollnir has +d5 to-hit and deals d24 extra shock damage against monsters without shock resistance, with a separate a ¹⁄₅ chance of destroying each wand and ring in the target's inventory. Mjollnir's lightning strikes will also wake nearby monsters.

A hero that has 25 strength (usually from worn gauntlets of power) and is wielding the non-cursed Mjollnir can throw it: Mjollnir travels up to six squares when thrown, which is roughly half the distance of a normal thrown hammer. For a Valkyrie, Mjollnir will return ⁹⁹⁄₁₀₀ of the time, and if they are not confused, stunned, blind, hallucinating, or fumbling when it returns, they will catch it ⁹⁹⁄₁₀₀ of the time. If a hero fails to catch a returning Mjollnir, it has an equal chance of falling at their feet or else striking them, possibly destroying wands and rings.

Strategy

Shock resistance is fairly rare among monster resistances throughout the initial stage of the game, making Mjollnir an excellent weapon for much of the game since it can deal a lot of shock damage, even with its low base weapon damage.

There are quite a few shock-resistant monsters that can be encountered by any character before the Castle: of those, blue dragons and storm giants are quite rare, and tend to appear on very deep floors and in throne rooms; electric eels can be evaded or killed with other attacks, ideally ranged ones; and puddings and gelatinous cubes are not especially dangerous in comparison to the other listed monsters, unless a player is careless, even with Mjollnir's low base item damage. Monsters such as energy vortices and the humanoid angelic beings are the primary dangers for a character using Mjollnir as their main weapon - note that wielding Mjollnir does not grant shock resistance.

As lawful Valkyries have access to Excalibur, they are much more likely to make it their main weapon for the damage bonus against all monsters, on top of the drain resistance and its lack of noise. Though the odds of having Mjollnir fail to return are minuscule, the fact that a chance exists at all is enough to put many players off the notion of throwing it - the chance of destroying rings and wands, whether on hostile monsters or in their own inventory, also deters players who seek to preserve loot for similar reasons.

Despite these drawbacks, Mjollnir is still a worthwhile artifact weapon for many neutral roles that seek one, especially Tourists and Priests. A character concerned about Mjollnir backfiring may consider a stack of daggers or other projectiles as their main thrown weapon against weak or slow-moving monsters, and treat Mjollnir as a backup weapon if they exhaust the projectiles or urgently need the extra damage. Beware throwing Mjollnir at a disenchanter: artifacts have a ⁹⁄₁₀ chance to resist the passive disenchanting, but if it occurs it will not produce a message like hitting a disenchanter in melee combat would.

From the Castle itself to the depths of Gehennom, shock-resistant arch-liches are one of the biggest obstacles for a character using Mjollnir, on top of often being a huge obstacle in general. Various other monsters such as green slimes, the Riders and hostile aligned priests (including the high priest of Moloch) also resist shock damage - green slimes and angelic beings can occur via the summon nasties monster spell, the Sanctum is full of hostile priests, and several angels and priests will be encountered on the Astral Plane alongside the Riders.

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that the information below is still accurate, then update the page to incorporate it.

Per commit 67295bc7, wearing non-metallic gloves (all but gauntlets of power) will protect worn rings from electrical damage; this may provide further incentive to avoid throwing Mjollnir as a Valkyrie. Conversely, extrinsic shock resistance protects open inventory from shock damage ⁹⁹⁄₁₀₀ of the time, making sources of that property more conducive for Mjollnir-throwing Valkyries.

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	$\frac{1+4}{2}+1=\bold{3.5}$	$\frac{1+4}{2}=\bold{2.5}$	$\frac{1+4}{2}+1+\frac{1+24}{2}=\bold{16}$	$\frac{1+4}{2}+\frac{1+24}{2}=\bold{15}$
+7 Mjollnir	$\frac{1+4}{2}+1+7=\bold{10.5}$	$\frac{1+4}{2}+7=\bold{9.5}$	$\frac{1+4}{2}+1+\frac{1+24}{2}+7=\bold{23}$	$\frac{1+4}{2}+\frac{1+24}{2}+7=\bold{22}$

History

Mjollnir first appears in NetHack 3.0.3. In NetHack 3.0.0, an artifact lucern hammer named Thunderfist was introduced, with Mjollnir replacing it in NetHack 3.0.3 - this is likely because the lucern hammer was a polearm mistaken for a "standard" hammer weapon.

Mjollnir's throwing requirements and special behavior for Valkyries are introduced in NetHack 3.1.0.

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 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

SLASH'EM

In SLASH'EM, Mjollnir's base item is changed to a heavy hammer, which is made of inherently erosion-proof metal and has slightly higher base damage (1d6 against both small and large foes); this change originated in NetHack Plus. As its base item is not randomly generated, Mjollnir can only be obtained through sacrifice, wishing, or bones.

The changes to artifact weapon bonuses make Mjollnir far more formidable with flat +5 to-hit and +24 damage bonuses - artifact weapons can also be twoweaponed in the off-hand, making Mjollnir a very powerful artifact overall and an especially enticing off-hand candidate. Mjollnir still remains somewhat weak against shock-resistant monsters, however, and its base item is only slightly stronger than a normal war hammer.

Gauntlets of power also behave differently, setting strength to 18/** when worn and augmenting it further based on enchantment, which makes obtaining 25 strength to throw Mjollnir using these gloves generally more difficult. Thankfully, Valkyries can safely enchant gauntlets of power to +7.

Average damage calculation

The damage calculation below assumes a player 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 a non-shock resistant undead/demon monster.

Weapon	Against regular non-shock resistant monsters	Worst case scenario	Best case scenario
Uncursed Mjollnir + 0	$\frac{1+6}{2}+24+2=\bold{29.5}$	$\frac{1+6}{2}+2=\bold{5.5}$	$\frac{1+6}{2}+24+2=\bold{29.5}$
Blessed Mjollnir +7	$\frac{1+6}{2}+7+24+2=\bold{36.5}$	$\frac{1+6}{2}+7+2=\bold{12.5}$	$\frac{1+6}{2}+7+24+2+\frac{1+4}{2}=\bold{39}$

dNetHack

In dNetHack, Mjollnir has +1d5 to-hit, and the war hammer is a stronger base weapon: Mjollnir deals 1d8+2d4+3 versus small monsters, and deals 1d8+2d4 versus large monsters, with additional +1d24 shock damage against all non-resistant monsters. Mjollnir can be twoweaponed in the off-hand by Valkyries, but is heavy enough with its default material that a medium-sized character cannot do so without incurring a to-hit and damage penalty. Mjollnir grants shock resistance and blindness resistance while wielded. Hitting with Mjollnir in melee randomly fires lightning bolts that deal 6d6 damage and blind, 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 or a valkyrie player monster 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, due to its weight it only has half the normal range a thrown projectile would normally have (i.e. STR/4, or 6 squares).

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 rely on twoweapon 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.