Probably pretty obscure. It's like a cheesy 70's, possibly British, evil horror where this guy goes to a mansion where there is a guy who's sister believes he is possessed by evil. The guy denies being evil while he is being investigated. He finds this underground cavern on his property where there is an altar and some demonic gorilla like beast. At the climax he discovers there are a bunch of women (some bare breasted) and midgets and others in red robes having some orgy-like ceremony where they're going to sacrifice a girl. One of the guys pretends he is going to carry out the sacrifice, but it turns out he was just acting and throws holy water on their leader and then pulls out a gun and shoots him. Asmadeus is mentioned somewhere. A succubus or something visits one of the guys toward the begging. It's in color. Hope someone knows.:o