Black Angus is a large black dog with yellow eyes and sharp fangs who roams the northern English and Scottish countryside showing himself to those who will die within a fortnight. Scottish Lowlanders claim he has horns on his head, which may have derived from some confusion with the Christian Devil. Like death itself, the hellhound speaks, but does not listen; acts, but never reflects or reconsiders. Driven by hunger and greed, he is insatiable and his growl is eternal in duration.

“Another belief is that there are ghostly black dogs, the size of large retrievers, about the fields at night, that these dogs are generally near gates and stiles, and are of such a forbidding aspect that no one dare venture to pass them, and that it means death to shout at them. In some places the spectral dog is named "Shuck" and is said to be headless.”

Rev Worthington-Smith's book on the folklore of Dunstable, published in 1910

In some mythologic tales, it is suggested that there is not only one but usually a pair of hell dogs, one being the dog of life and the other the dog of death, serving to carry off one about to die, while the former can restore him or her to life. In the Armenian mythology, one hound is named Spitak, 'the White', and the other the hound of death, Siaw, 'the Black'. In the Greek mythology, Cerberus is sometimes mentioned along with his brother.

Odin has two hounds who keep ceaseless watch - one sleeps by day and the other by night - outside the castle of Mengloth.

One is called Gifr,
and the other Geri,
if you want to know that;
very ancient guards
and they keep guard
until the gods are torn apart. Fjolsvinnsmal

The names of these hounds, Gifr and Geri, are closely linked to words meaning 'greedy', understood to mean hungry for the flesh of the dead.