Living Doll Collectors are TV Tropes-popularized term about mentally disturbed character, usually a villain or antagonist whom have disturbing obsession to collect dolls that made out of their victims.
Who Are They and What Made Them Different With Sane Doll Collectors
Many people has had a doll/action figures back in their childhood, where they used to played with or even imagined as their friend when playing them. Even after they grow up into adults with more mature mindset, these people may still love to collected them, either as hobby or as part of instrument to tell stories as puppeteers.
Unfortunately, some of these people's affection with dolls grew into unhealthy level, to the point they began to perform either kidnapping, brainwashing, or worse, murder on innocent people and played as their "dolls". These kinds of people are called Living Doll Collectors. How they developed into such character was ranged from twisted childhood or in lesser extent, personal obsession that drove him/her insane, so insane that regular dolls won't appease them.
The difference between Living Doll Collector and Sane Collectors is very clear: Whereas regular doll collector preferred to collect regular dolls and may not let their obsession twisted their mind, Living Doll Collector's mind was has already twisted to the point that they made dolls out of living people.
Methods to Turn Other People Into Dolls
Living Doll Collector's methods in turn other people into collection of living dolls are various, ranging from drug usage, dark magic, brainwashing, etc. Murder and desecrating a victim's dead body into dolls is not always the case, as some prefer to render them under brainwashed/vegetative state so they can either play/abuse them like with regular dolls do.