They are described as large, dark beasts similar to a dog, but larger. The size is about half that of the player's character, and the Hellhound has a muscular build similar to a Boxer. The fur is pure black, and the creature's eyes are bright red, making it hard to see during the night.
Reports claim that the elusive beast cannot be killed, as it moves extremely fast and tries to stay out of the player's line of sight before moving in for a kill. Many eyewitnesses say that they have heard growling noises and felt uneasy, and could see something stalking them in the distance, minutes before the inevitable attack.
GTA San Andreas
The most common sighting place for the Hellhound is surprising, the backyard of Lance Wilson's, known as Ryder, home. There are many reasons as to why, but most sightings can be debunked as being the floating shovel that spawns in Ryder's backyard. Some fans have tried to theorize other options, including the humorous theory that the Hellhound is just a dog who ate Ryder's drug plants and could not control itself. Ryder was a drug dealer, murderer, and more, so some religious players believe that the Hellhound serves as the "punishment" for his sins, as they believe the hound is, quite literally, from Hell. In real life, Hellhounds are believed to be the ones that take souls to Hell, so this could be a plausible theory. There have been minor sightings across the San Andreas countryside, including prominent appearances in the Mount Chiliad caves, but these claims are not believed by the majority of the myth community.
There is a severe lack of evidence for the Hellhound's existence within GTA IV. However, a small fringe group of hunters still believe it could be real. Sightings of the beast vary in time, and it's believed they can be seen in any time of the day, unlike its other counterparts which can only be witnessed at night. A more popular claim is that the Hellhound is not actually demonic in nature, but could be the consequence of a Peach Island experiment went wrong. The main sightings for Hellhounds in GTA IV are Middle Park, and the Abandoned Hospital. However, something that is unique to this myth is that eyewitnesses have claimed to see the creature assaulting pedestrians and the player in the city district of Broker.
In GTA V, this myth has more credibility as Rockstar Games had officially added animals to the game, dogs included. The most common explanation for Hellhounds in GTA V is that the so-called beast is actually just a regular dog, except that it is missing a texture and is aggressive towards the player. Many dogs in vanilla GTA V are aggressive to the player already, so the claim of dogs attacking the player should not be considered as part of the Hellhound myth. There is no visual evidence to back up many of the claims made by believers, but the existence of Humane Labs and Research lends plausibility to the myth. Hellhounds are mostly encountered at night and can be found in the mountain ranges of San Andreas, mostly on Mount Chiliad and Mount Josiah. There are minor claims of Hellhounds found within the subway system, but these are believed to be stray dogs and not paranormal.