The increasingly jagged, incoherent quality that overtook Italian Gothic horror films in the ‘70s resulted in some truly odd films like The Devil’s Wedding Night, Death Smiles on a Murderer and Black Magic Rites that work more like perverse fever dreams than normal narratives. Also among that delirious company is the memorably titled Byleth: The Demon of Incest, which uses the idea of brother-sister lust as the hook to hang a tapestry of possession, murder, nudity, and general madness.
Part of a brief foray into horror and thriller cinema by director Leopoldo Savona (who also helmed the very entertaining Death Falls Lightly the same year), this sordid tale presents the traditional demon of Byleth as an entity capable of inducing incestuous feelings in mortals – in this case Duke Lionello Shandwell (Damon, testing out that hint of mascara he sported in the aforementioned The Devil’s Wedding Night), who gets all hot and bothered when his sister Barbara (Gravy) comes home after a lengthy sojourn abroad. Now she’s married to Giordano (Landi), and while someone in the area is killing ladies of the evening, she finds herself the object of her brother’s darker urges. Is there a demonic influence at work, or is it just old-fashioned human evil?
Despite coming out at the height of the giallo era and featuring a handful of token slayings, this potboiler definitely marches to its own drum with a strange pace that makes plenty of room for both family drama and bare flesh in equal measure. You also get a nice atmospheric score by the still relatively ignored Vasco Vassil Kojucharov, a wacko spook house of a finale, and a one of the greatest actress names for a leading lady in movie history thanks to Claudia Gravy (whose real birth name, Marie-Claude Perin, isn’t remotely as catchy).
As with a lot of other European genre films around the same time, this one was largely overwhelmed in the tidal wave of offerings in 1972 and barely received any initial play outside of Italy. However, the film was given a significant release the following year in Germany, apparently with extra nudity via body doubles and additional shots added compared to the original cut (which evidently hasn’t been released on home video). In any case, the extra spicy German version first turned up in an English-friendly subtitled edition from X-Rated Kult, albeit in a flat letterboxed transfer. Far better is the 2019 edition from Severin Films, available as separate Blu-ray or DVD editions and culled from what is described as the only uncut negative elements in existence, the German version under the title Trio der lust. It's a very modest looking film with pretty drab flesh tones and basic lighting, but for what it is this should be more than enough to please fans and serve as a worthy upgrade. The LPCM German and Italian tracks are offered, both sounding fine for less than dynamic mixes in the first place, with optional English subtitles provided (translated from both versions). Buying options for this one include Blu-ray, DVD, and if you're jonesing for a big dose of Italian horror, a "ByPagThrope Bundle" packaged with Paganini Horror and Werewolf in a Girl's Dormitory.