One of the things I liked most about the series Moonlight was that the mystery of the week wasn't always due to a vampire. They existed, occasionally they were a problem, but so were people.
Whether you make it a book or a series, make sure that various creatures aren't the explanation for everything
that happens (as seems to be the case with some of the Urban Fantasies).
It gets a bit much when you read a fantasy and it turns out that everything we know about our society is the way it is due to the influence of supernatural creatures. They take over the whole story. Hindenburg? Due to warring ghoul factions. World War Two? A long-term plan by the Tucheezi Vampire clan. Having three meals a day? Vampire custom from the dawn of time. Eat toast for breakfast? Invented by werewolves because handwave
. And so it goes.
And then every little plot is due to them as well.
That's the point where it gets too unbelievable for me: not "having too many different types of creatures" as such, more "having them responsible for too much of the plot and backstory."
Sure, having 15-20-foot giants somehow not being noticed for centuries, especially if they're in large enough numbers for a stable population, would probably stretch credibility to breaking point, so you'd have to have some damned plausible reason no one noticed that the neighbour occasionally takes up an entire elevator by himself. Or decide that, nah, there are no giants wandering around.
edited 15th May '13 9:23:14 PM by Wolf1066