Horg is Dr. Mordenheim's assistant, in the classic Fritz/Ygor graverobber tradition (following a taste for cinematic themes, Dennis Mize has sculpted him to resemble Dwight Frye from the 1931 Frankenstein film, much as he also used the movie as a basis for Mordenheim himself).
The only note about the paint job is that there's something about olive drab and brown that seems to make good clothing colors for graverobbing lackeys; another hunchback mini from the old Grenadier Creatures of the Night set ended up with the exact same clothing scheme, with me oblivious to the fact until much later...