Grim

A Grim (also known as a black dog) is the name given to a being found primarily in the folklores of the British Isles. Cookie Souris is the owner of a Grimfang Glove, said to made from the hide of such a beast.

History
The black dog is essentially a nocturnal apparition, often said to be associated with the Devil or a Hellhound. Its appearance was regarded as a portent of death. It is generally supposed to be larger than a normal dog, and often has large, glowing eyes. It is often associated with electrical storms (such as Black Shuck's appearance at Bungay, Suffolk), and also with crossroads, places of execution and ancient pathways.

The origins of the black dog are difficult to discern. It is impossible to ascertain whether the creature originated in the Celtic or Germanic elements in British culture. Throughout European mythology, dogs have been associated with death. Examples of this are the Cŵn Annwn, Garmr and Cerberus, all of whom were in some way guardians of the underworld. This association seems to be due to the scavenging habits of dogs. It is possible that the black dog is a survival of these beliefs. Black dogs are almost universally regarded as malevolent, and a few (such as the Barghest) are said to be directly harmful. Some, however, like the Gurt Dog in Somerset and the Black Dog of the Hanging Hills in Connecticut, are said to behave benevolently.

Abilities
Grims are said to have the ability to easily tear the barrier between the Nevernever and the real world, allowing them to make frequent appearances in the mortal realm. While this is done using their jaws, the actual hide of the Grim is claimed to bear this ability.