Actually, the Angel of Death rides in, but let's not be too picky. This old Hammer classic, which I watched recently for the first time in many years, is great fun. When I was a kid it was one of those films that you badgered your parents to let you stay up and watch. It seems as far from today's standard horror flick as Mercury is from Neptune,
The film begins with a biplane landing near a yellow Rolls Royce, so we are presumably in The Past, among Posh People. Sure enough, the Duke de Richleau (Christopher Lee) is at the aerodrome somewhere near London to greet old pal Rex (the not-very-exciting Leon Greene). It emerges that a son of an old pal, now deceased, has gotten into bad company. Simon Aron, played by Patrick Mower(!) has fallen in with a coven. And so Richard Matheson's adaptation of Dennis Wheatley's novel sets off on an odyssey of Satanism, religiosity, a bit of romance, and a vintage car chase.
The between-the-wars feel is well done and the villain, Mocata, extremely well-played by Charles Gray. Lee takes the job seriously, clearly relishing Cushingesque role of a goodie with occult knowledge. Few Hammer films look this good, scoring at least 9/10 on the Poirot scale for period feel. The dialogue, despite being heavy with exposition, never strays into the ludicrous, and the performances are generally good to excellent.
Any flaws are really those of Wheatley's plot - such as the appearance of 'the devil himself' well before the movie's climax, and the shift of emphasis to human sacrifice. Some scenes seem a bit tacked-on. But the faults are outweighed by the virtues of a full-blooded, old-school Good v. Evil conflict that is as well-realised as any in horror cinema.
In a sad coda, the success of this one led Hammer to film Wheatley's To The Devil A Daughter, a failure that more or less scuppered the studio. Some evils can't be dispelled with a dash of holy water, and that goes double for bad movies.