In Norse mythology, the monstrous hound Garm was the servant of the goddess Hel and guarded the entrance to Helheim, the realm of the dead. Garm had four eyes and a chest drenched with blood. The monster hound lived in the Gnipa cave, near the entrance to Helheim. Anyone who had given bread to the poor in life could appease Garm’s anger with a special treat called Hel cake.
On the day of Ragnarok, the final battle, it was believed that Garm would join the giants in their fight against the gods. In one version of the story, Tyr, the god of war, killed the hound but died from the wounds that Garm
had inflicted.
Garm is often equated with the monstrous wolf and savage enemy of the gods Fenrir. In most versions of the story of Ragnarok, it is Fenrir, not Garm, who slays and is slain by Tyr.
SOURCE:
: Storytelling – An Encyclopedia of Mythology and Folklore. Edited by : Josepha Sherman