Not sure how I'd overlooked this for so long, but I'm so glad to have recently stumbled upon it.
It was like a Jean Rollin film washed-up in California. Instead of the desolate beaches and deserted chateau's of the old world, Messiah Of Evil conjures up an eerily similar vibe in modern Malibu beach houses and Californian artist colony locales.
One of the finest American indie horror films of the 1970's