One of the few success stories of Stone Mountain, Georgia outside of the Ku Klux Klan.
Mark Rein-Hagen used it as a production company for his Ars Magica role playing game - but then decided on a simpler roleplay system called Storytelling in which the mechanics of game play were vastly simplified to allow for more organic storytelling. This was in opposition to existing role playing games which to that point were based on tatctical battlefield desktop simulations and therefore relied on dice rolls and adjudicating rules. They started with Vampire: The Masquerade in which the player characters were human beings who had been chosen by a hidden vampire society to join one of its "families" - each with a different trope. If angst and homoerotic undertones were your thing, you could live in the world of The Vampire Lestat with the "Toreador" "clan". They also had the Nosferatu (no explanation needed], Brujah (think: "Lost Boys"), "Ventrue" (think Donald Trump as a vampire), Gangrel (a wandering nature-based vampire who communed with animals). The player-selectable "clans" were collectively called the Camarilla, and the opposing ones were the Sabbat.
Both had differing methologies to limit behavior - whereas Dungeons and Dragons had the concept of alignments the game had as its premise that the vampire always had to fight its bestial nature, and once it lost all its Humanity (which was lost by committing greater and greater atrocities) it would no longer be a playable character, and would probably be hunted down and killed. The Sabbat had a "Blue and Orange" style morality and for a while was not a player-selectable option.
But they parlayed a simplified system, a rich and evocative setting, and its use of outdated words (camarilla, gangrel) into a juggernaut, selling tons of books, merchandise and more. The kind of girl who didn't find enough attention paid to her in drama club and the kind of boy who was on the Goth axis of the Hot Topic client base flocked to it in DROVES. Characters could ULTIMATELY win by a transforming question that either restored humanity (Vampire) or solved the crises of a past life (Wraith), but that was a rarely used option.
They had a great tie in with the World Wrestling Federation, who produced a "vampire" wrestler named Gangrel. He later became a porn star. But that's another story.
Expansions soon followed, cookie-cutter style. Player can be $MONSTER_TYPE of $FAMILY_CLASS in $GOOD_GUY_GROUP versus $BAD_GUY_GROUP but must guard against $ENTROPY_IMPULSE or lose his character. Ghosts (Wraith) had to wander the earth to settle whatever score kept them tied between a final resting place, and living existence. Vampires had to eke out a life in the shadows, playing vampire politics with others until they either go Bestial, slde into a permanent sleep, and so forth. "Hit Points" varied between systems as well. Blood Points were a measure of vampire health, and could be "expended" to take magic-like actions. Wraith had "Corpus" (basically, ectoplasm). Mage had a similar system but instead of a spell list like in Dungeons and Dragons, you could do anything you could conceivably describe so long as it fit in with your archetype, wasn't an unreasonable use of power given your experience level, and had no witnesses. Werewolves were actually warriors serving Gaia against a consuming corrupting creature called "The Wyrm". And the worlds could colide, and did.
And you were encouraged to do something called LARP - Live Action Role Playing. In other words, you did the same thing you did when you were kids and pretended to be characters on a show, running from playground to playground, perhaps with a toy sword or cap gun. Which is pathetic when you're college aged, and pretending to be a vampire. Especially when you're Goth and taking it way too seriously.
It didn't age well, because there was a LOT in its content that was unashamedly RACIST. There were a family of Irish Werewolves who basically were prone to living in trailers and fighting for a few gallons of red diesel and cheap whiskey. Gypsies had explicit powers of lying and thievery, because their lot in life was to go around stealing things. There was a family of Italian vampires who were every bit the "bada boom, bada bing" Sopranos style goombahs trope - complete with incestuous necromancy. And of course people of black descent were all noble savages complete with every dreadlocked, "magical Negro" stereotype. You could practically hear the native flutes going when they got to the American Indian. As society got more and more politically correct, the numbers of people who played the game dwindled but were not replaced by newcomers. The author of the Gypsy source material tried in vain and failed to defend her work, arguing that she had thoroughly researched her source material and had great respect for the Roma people - but come on guys, when you see them in the films.... they're thieves and it's what the punters want, right? Role Playing in general learned from this experience and when the latest Dungeons and Dragons version hit the newsstands, they were EXTREMELY CAREFUL in the Ravenloft setting to make sure the "Vistani" were NOT EXPLICITLY HUMAN AND NOT GYPSIES and any similarity or flavor was PURELY COINCIDENTAL.
Vampire tried way, way too long to get a MMPORG presence: they partnered with an Icelandic game manufacturer who released far too little, three decades too late. They retooled their material, completely reinventing the storytelling arena (The World of Darkness) but it was confusing and too far removed from the original premises to work.
You can still find many of the books in used bookstores in the Atlanta area - with the exception of the Gypsies source book simply because it became a collector item for the same reason TinTin visits the Congo became one. But it made the 1990s a real blast, and changed role playing from "kill kobolds, amass gold, level up" to something far more personal.