Wiktionary
hell hound
n. (alternative spelling of hellhound English)
Wikipedia
Hell hound (Dungeons & Dragons)
In the Dungeons & Dragons fantasy roleplaying game, the hell hound is a hyena-like creature which can breathe fire and hunts in packs. It is classified as an outsider from the Nine Hells.
Usage examples of "hell hound".
This time, however, he'd follow the trail of memories to the end as doggedly as any Hell hound, surprising the Old Mage and perhaps, just perhaps, breaking the human's mind at last.
But if you're wicked enough, and if you die and go to Hell, maybe you'll be transformed into a hell hound, like me.