Garm was the monstrous hound of the Norse underworld — the blood-stained dog that guards the gates of Hel, the realm of the dead, and who is fated, at Ragnarök, to break loose and fight the god Tyr, each slaying the other. He is the hellhound of Norse myth, the howling guardian whose breaking free is one of the signs of the world's end.
The Hound of Hel
Garm (Old Norse Garmr) was a great and terrible dog, described as blood-stained, who guarded the entrance to Hel, the realm of the dead, dwelling at a cave called Gnipahellir before the gates of the underworld. He was the watchdog of death, baying and howling at the boundary between the living and the dead, the fearsome guardian who kept the dead within and the living out. As the wolf Fenrir was the great bound beast of the worlds above, Garm was the monstrous hound chained at the threshold of the world below.
The Howl That Heralds the End
Garm's howling was bound up with the coming of Ragnarök. In the great prophecy of the world's doom, the refrain returns again and again: “Now Garm howls loudly before Gnipahellir, the fetter will break and the wolf run free.” The baying of the hound of Hel was one of the great omens of the end — the sound that signalled that the bonds were breaking, that the monsters were loosing, that the doom of the gods had come. When Garm's howl rose before the cave of the dead, all the worlds knew that the end was at hand.
The Battle with Tyr
At Ragnarök, Garm breaks loose from his fetters and joins the forces of chaos against the gods. On the final battlefield, the hound of Hel meets the god Tyr — the one-handed god of war and justice, who had once sacrificed his hand to bind the wolf Fenrir. The two fight, and they destroy each other: Garm and Tyr each deal the other a death-blow, the monstrous hound and the brave god falling together. (In some readings, Garm is closely associated with, or even identified with, Fenrir himself, but in the tradition of the final battle he is the hound that Tyr fights and falls against, as Odin falls against Fenrir.)
The Hellhound of the North
Garm endures as the great hound of the Norse underworld — the blood-stained guardian of the gates of Hel, the howler whose baying heralds Ragnarök, the beast fated to slay and be slain by Tyr at the end of the world. He is the Norse counterpart to the hellhounds and underworld-guardians found across many mythologies (kin in role to the Greek Cerberus), and he embodies the Norse vision of death as a guarded realm, watched by a terrible hound, and of the end of the world as a time when even the hound of death breaks loose and the guardian of the dead joins the war against the gods.
The blood-stained hound bays before the cave of the dead — and when his howl rises and his fetter breaks, all the worlds know that Ragnarök has come.