In Greek, English, and Native American folklore, the Hellhound is commonly seen as an omen of death. If you see it once, you will likely die within the next year, and if you see it three or more times, you're definitely going to die soon. You are more likely to see a Hellhound while traveling at night around a wooded area, as these creatures are nocturnal.
The Hellhound is generally depicted as a large dog—its sizes ranging from that of a mastiff at its smallest to the size of a horse or bear—with a coal black pelt and glowing red or green eyes. They are sometimes depicted as having multiple heads or as being headless. Though the Native American Hellhound, the Cadejo, is said to have a white or black pelt and goat hooves, occasionally including horns in their appearance.
In Greek mythology, the most recognizable Hellhound is Cerberus, the three-headed protector of the Underworld, and in English folklore, there are many different depictions of the Hellhound. One of the most common depictions being Black Shuck, who supposedly attacked a church, killing two people and causing the church steeple to fall through the roof. Though there have been multiple accounts of Black Shuck being hostile and attacking churches or other religious grounds, there have also been reports of Black Shuck saving a rape victim, or guiding travelers during the night. Another Hellhound in English folklore includes the Yeth Hound. This headless Hellhound will travel at night, and its wail is considered a death omen.
The Hellhound has several supernatural abilities which include above average—for their size and body shape—speed and strength, shapeshifting abilities, conjuring mist cloaks, or vanishing on the spot. One of the examples of the Hellhounds' shapeshifting abilities is the Barghest. This Hellhound from English folklore commonly appears as a headless old lady, a white cat or rabbit, or the common black dog. Hellhounds also possess the ability to scorch the ground where they walk, use pillars of fire for transportation, or make their claws hot as flame.
There are several interpretations of what the Hellhound does, whether it be guiding travelers through the night and protecting them from harm like the white Cadejo from Native American folklore, hunting down and killing travelers like the black Cadejo, attacking churches, guiding spirits to the Underworld of Otherworld, or just being a death omen.