Garmr

In Norse mythology, Garmr or Garm (Old Norse: Garmr ) is a wolf or dog associated with both Hel and Ragnarök, and described as a blood-stained guardian of Hel's gate.

Name
The etymology of the name Garmr remains uncertain. Bruce Lincoln brings together Garmr and the Greek mythological dog Cerberus, relating both names to a Proto-Indo-European root *ger- "to growl" (perhaps with the suffixes -*m/*b and -*r). However, Daniel Ogden notes that this analysis actually requires Cerberus and Garmr to be derived from two different Indo-European roots (*ger- and *gher- respectively), and in this opinion does not establish a relationship between the two names.

Poetic Edda
The Poetic Edda poem Grímnismál mentions Garmr:

The best of trees | must Yggdrasil be, Skíðblaðnir best of boats; Of all the gods | is Óðinn the greatest, And Sleipnir the best of steeds; Bifröst of bridges, | Bragi of skalds, Hábrók of hawks, | and Garm of hounds.

One of the refrains of Völuspá uses Garmr's howling to herald the coming of Ragnarök:

Now Garm howls loud | before Gnipahellir, The fetters will burst, | and the wolf run free; Much do I know, | and more can see Of the fate of the gods, | the mighty in fight.

After the first occurrence of this refrain the Fimbulvetr is related; the second occurrence is succeeded by the invasion the world of gods by jötnar; after the last occurrence, the rise of a new and better world is described.

Baldrs draumar describes a journey which Odin makes to Hel. Along the way he meets a dog.

Then Óðinn rose, | the enchanter old, And the saddle he laid | on Sleipnir's back; Thence rode he down | to Niflhel deep, And the hound he met | that came from hell.

Bloody he was | on his breast before, At the father of magic | he howled from afar; Forward rode Óðinn, | the earth resounded Till the house so high | of Hel he reached.

Although unnamed, this dog is sometimes assumed to be Garmr. Alternatively, Garmr is sometimes assumed to be identical to Fenrir. Garmr is sometimes seen as a hellhound, comparable to Cerberus.

Prose Edda
The Prose Edda book Gylfaginning assigns him a role in Ragnarök:
 * Then shall the dog Garmr be loosed, which is bound before Gnipahellir: he shall do battle with Týr, and each become the other's slayer.

In popular culture
Garmr is the namesake and emblem of the Galm Team in the combat flight simulation game Ace Combat Zero: The Belkan War. The name "Galm" is a mistransliteration of "Garmr" into English due to the singular liquid phoneme in the Japanese language.

Garmr appears as a boss fight in the 2017 video game Hellblade: Senua's Sacrifice and 2022's God of War Ragnarök.