Alright, so he kidnapped the kids when they were children, and raised them in his hellish basement prison to turn them into what they were in the movie. How did he do it, though? I've pieced together that he coupled large amounts of PCP and sensory deprivation over the course of 10 years. Does that sound right?
sharePCP was for strenght and also for brainwashing. And keeping them for 10 years in cells, in dark, with no human contact (not even between them), they have lost humanity. By torturing them (with his "treatments"), he finally made them turn against humans and thats where the rage came from.
Keep a dog in a leash for a couple of years and then release him in the streets...
That's as good an explanation as any, certainly better than anything supplied by this film. I was surprised to see PCP (better known as "angel dust") referenced in this film. That was the big scare drug of the early '80s. "60 Minutes" did a story on it where they showed people freaking out on it. And a lot of people were smoking it unknowingly when their joints were laced with it.
Anyway, it's an intriguing topic for a film, but not adequately addressed here. This film started out strong and then turned into your standard exploitation film about a psycho killer film (qu'est-ce que c'es).