[Kereth]

Well, if you're determined to have a vampire theme, you could try some browser games like Monster's Game, but that's essentially roleplay free, just a vast, uncomplicated werewolves vs. vampires pvp setup. If you're going for "interractive fiction," you could try some other kinds of MU*'s, or some kind of interactive storytelling thing based in a message board or whatnot. I think Starpool Holt is one of those my wife was into at one point, but that's themed around the ElfQuest comic series, and hardly vampires.

Now, if you want interesting character generation, you could try RetroMUD , which has vampires, yes, along with 60 or more other races to choose from. It's also extremely well documented, with helpfiles for just about everything and a good community to help you learn your way around when you can't find the file for what you need, so you don't need to worry about it being a novice to MUDs.

As for interractive fiction in a MUD environment, you're going to have to look at varying degrees. Any MUD that offers roleplaying will be a good choice, to get some from that angle. Quests vary in quality. Some MUDs, such as Discworld MUD, do have a few of the "kill X number of (blah)" quests, though Discworld mingles it with humorous quests like slapping some random guy with a fish (and bang! You get exp! That was a quest?) I've yet to play a MUD where every quest was part of a central story, but RetroMUD at least has six worlds of individually themed quests, completely devoid, to my knowledge of any quests involving farming a certain number of token monsters. It has a fair number of quests to slay some evil (or good) overlord and loads of miscellaneous ones, such as freeing tribes of the sources of greed that have spawned generations of conflict, solving the mystery of a cursed island, saving the boy who got lost in the woods, saving the whole universe from an evil overlord who is going to shatter the very fabric of reality, and so forth, going on to a vastly extensive list which won't even begin to fit here, varying of course, from things like the "find the boy" quest which can be done in minutes to quests like the latter, which takes weeks, even months of time to work all the way through.

Speaking to NPCs: This is one area will I will recommend discworld. Many MUDs, such as RetroMUD, will have you interract with npcs through the use of "ask" commands or whatnot (as in, "ask (npc) about (question)") A few, like discworld, have nice parsing systems, so you can just ask the question normally, and the npcs will respond to key words as if they understood you. This is nice for the dedicated role player who wants to treat random npcs as living, breathing people, though even that falls through eventually, but it also has the interesting trait of letting you say derogatory things about their mothers that happen to use the key word and still illicit the desired response.

Anyway, that's all I know about the stuff you're looking for. Hope you found something in there that helped.
-Kereth