A Hellhound is a psychopomp demon and a type of Reaper created by Death in order to help him sort deceased souls into their correct afterlife. A Hellhound differs from standard Reapers in that they have a spiritual form with the capability of interacting with souls. With this ability, Hellhounds are usually tasked with forcibly reaping souls who refuse to follow a standard Reaper into the afterlife.
When a soul refuses to leave Earth, they become a ghost. Ghosts can wander, and sometimes need to be tracked by Hellhounds before they can be reaped. The spiritual form of a Hellhound is a canine form, and only in this form are they able to interact directly with souls.

Hellhounds were purposefully based on dogs by Death for a variety of reasons that make them better at their bounty-hunting role than a standard Reaper would be. While their corporeal body shares many of the same qualities as typical Reapers, they retain the following canine traits:
- Canine ears
- Canine tail
- Thicker nails (many Hellhounds clip purposely into sharp claws)
- Prominent canine teeth
- Heighten sense of smell and hearing
- Heightened libidos
- A "dog-like" odor
Unlike standard Reapers, Hellhounds are directly employed through Death. As Reapers hold a large position in the funeral industry in America, Death is able to salary his Hellhounds through the profits.
While their line of work may be similar, standard Reapers often disassociate from Hellhounds. In the cryptid community, Hellhounds have a negative and often fearful reputation, associated with brutality and aggression due to the nature of their work. This results in a cliquey nature among Hellhounds.