Mjollnir

)   Mjollnir
Base item	war hammer
Damage vs. small	1d4+1 +1d24
Damage vs. large	1d4 +1d24
To-hit bonus	+1d5
Bonus versus	not shock resistant
Weapon skill	hammer
Size	one-handed
Affiliation	neutral (Valkyrie)
When carried	(none)
When wielded	throwable
When invoked	(none)
Base price	4000 zm
Weight	50
Material	iron

Mjollnir (colloquially Mojo) is an artifact weapon that appears in NetHack. It is neutral for wishing purposes, and its base item is a war hammer. It is the first guaranteed sacrifice gift for Valkyries.

Generation

Mjollnir is eligible for random generation: a war hammer has a ¹⁄₄₀ chance of being Mjollnir, or ¹⁄₂₀ if Ogresmasher has already been generated. In addition to Valkyries, any neutral character may receive Mjollnir as a random sacrifice gift.

Effects

Mjollnir has +d5 to hit, and deals d24 extra shock damage against monsters without shock resistance; it may destroy wands and rings in the target's inventory in either event. Mjollnir's lightning strikes will also wake nearby monsters.

If Mjollnir is not cursed and you have 25 strength (e.g. from gauntlets of power), you can throw it; if you are a Valkyrie, Mjollnir will return to you 99% of the time. If it returns, and you are not confused, stunned, blind, hallucinating, or fumbling, you will catch it 99% of the time. If you fail to catch a returning Mjollnir, it has an equal chance of falling to your feet or striking you, dealing shock damage and possibly destroying wands and rings.

Strategy

Very few monsters in the game resist lightning damage, and Mjollnir does a lot of it, making it an excellent weapon for a majority of the game. However, though the odds of throwing Mjollnir backfiring are miniscule, 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 deters players who seek to preserve loot for similar reasons. Despite these drawbacks, it is still a worthwhile weapon for many neutral roles; as lawful Valkyries have access to Excalibur, they are much more likely to make it their main weapon for the drain resistance, the lack of noise and the damage bonus against all monsters.

There are few shock-resistant monsters usually encountered before the Castle: blue dragons are quite rare, storm giants are often not seen until Gehennom, and electric eels can be evaded and killed with other ranged attacks; puddings and gelatinous cubes are not especially dangerous in comparison to these, even with Mjollnir's low base item damage. Energy vortices are the primary danger if you are relying on Mjolnir as your main weapon and lack shock resistance (which Mjollnir does not provide).

From the Castle itself to the depths of Gehennom, arch-liches are also one of the biggest obstacles for a player using Mjolnir. Various other relevant monsters such as angelic beings, 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 as summoned nasties, the Sanctum is full of hostile priests, and most of the listed monsters are encountered on the Astral Plane.

Beware throwing Mjollnir at a disenchanter: Mjollnir still has a ¹⁄₁₀ chance of being disenchanted, and does not produce a message if this happens like hitting a disenchanter in melee combat would.

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

Before Mjollnir was introduced, an artifact lucern hammer named Thunderfist was present in NetHack 3.0.0; in 3.0.3, it was replaced by Mjollnir, evidently due to the fact that the lucern hammer was a polearm mistaken for a "standard" hammer weapon.

The throwing requirements and special behavior for Valkyries first appeared 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

Mjollnir's weak base damage is somewhat ameliorated in SLASH'EM, where it is instead a heavy hammer with base damage of 1d6 against both small and large foes. In addition, changes to artifact weapon bonuses mean that Mjollnir has +5 to-hit and +24 damage, making it far more formidable; gauntlets of power behave differently, however, meaning that obtaining the strength to throw Mjollnir is more difficult.

Average damage calculation

We assume the player has 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	$\frac{1+6}{2}+7+24+2=\bold{36.5}$	$\frac{1+6}{2}+7+2=\bold{12.5}$	$\frac{1+6}{2}+7+24+2+\frac{1+4}{2}=\bold{39}$

The largest damage boost in vanilla NetHack, percentage-wise, is a +0 Mjollnir attacking regular non-shock resistant large monsters. (+68.6%)

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.