In 1958, director Charles R. Rondeau followed up his first feature, The Littlest Hobo, with a low-budget horror/mystery picture in which a strange young man, who apparently can't sweat, drifts into a small town after his grubby Satanist uncle croaks. Soon various animals begin killing the locals while the nephew gets himself a sweet deal working at a gas station. No rational person would include The Devil's Partner on a list of classic horror movies, but it's reasonably well made with an effectively creepy lead performance from Ed Nelson (who most might remember from his regular role on Peyton Place, but those more likely to dig this flick will recall from the "Valley of the Shadow" episode of Twilight Zone), a tight little script, a fair dose of originality, and one genuinely creepily shot scene in which a horse stomps a rummy.
Roger Corman liked The Devil's Partner well enough to scoop it up for his Filmgroup distribution company and slap it on a double-bill with his own Creature from the Haunted Sea in 1961. Loopier, trashier, and overflowing with anarchic attitude, Haunted Sea is definitely the more memorable picture, with its wacky Cuban counterrevolutionaries and cue-ball-eyed monster made of Brillo pads. However, The Devil's Partner is the picture that leads the Film Masters' new 4K-restored blu-ray double-bill. That's probably because Partner looks way better, nearly flawless, in fact, in a blemish-free presentation with natural grain and no irritating enhancements. Haunted Sea comes from rougher stock, but a restoration-comparison video included as an extra shows just how far the image came from the scratched, blurry 35mm print used for this very pleasing if imperfect restoration. I doubt you'll see the movie looking better, under the circumstances.
Both films are included in both their 16:9 theatrical and 4:3 TV aspect ratios, and both films gained a lot more information at the top and bottom of their respective pictures on the boob tube. Creature from the Haunted Sea also gains a whopping fifteen minutes of extra footage in its TV form. There are also audio commentaries (a silly one by some podcast guys for the main feature and a more impressive roster of Corman, location manager Kinta Zertuche, film historian Tom Weaver, and contemporary B-movie director Larry Blamire for Haunted Sea), two-Corman centric featurettes, and even a couple of booklet essays, making for a very nice package.