Faelan

Faelan is a dark spirit that lives among the demons but occasionally passes the barrier into the mortal realm. His raises and trains hellhounds, teaching them to defend the barriers of the underworld so no humans get in and no demons get out. He's done this for millennia and intends to continue for the rest of eternity. He is a quiet, mysterious man rarely seen by human eyes. Your hometown recently spotted one of his hellhounds. Somebody managed to wound it before it ran off, and the town sent you to destroy it. You track it back to its lair, but you weren't quite ready for what you would find...