Yeah but quite importantly, Vampire: the Masquerade was a seminal work about being a vampire in the modern era, and its offshoots like Werewolf: the Apocalypse, Mage: the Ascension, etc, were basically what made the "urban fantasy" craze we saw in the 2000s. It's hard to convey how much fiction was downstream of World of Darkness. And it was because Mark Rein-Hagen and his crew were legitimately good at what they did in the 1990s.
They had a lot of very cool ideas, like the Biblical Caine being the first vampire, and vampires being these literal parasitic murder-monsters, who are more or less ontologically evil. Then throwing in the mix that you're supposed to be, as player, resisting that, with Humanity rating that can go down as you commit more sins. Then finally throwing in the mix that the obviously practical thing to do is often a Humanity violation, and it explains why these 3,000yo methuselah vampires are absolutely psychopathic, because on the one hand, drinking the blood of children is evil, but on the other hand, you gotta do what you gotta do, and on a long enough timeline your choice really will boil down to doing the bad thing or seeing Final Death.
They had mirrors of this in other splats. And again, it was legitimately compelling writing. There's a bunch of other cool ideas that I won't delve into, but Hagen's approach to morality is a good start. Now imagine them taking this really cool framework, and then producing...
Rudi.