I DMed a few campaigns and single adventures in Warhammer Fantasy Roleplay (2ed), but honestly, I always treated the lore very loosly.Mostly because Warhammer is such a grimdark world, and I wanted the game to be fun, and also I didn't want to get bogged down in stuff that some players, knowing the world would endlessly dispute, while those who don't know it would feel all lost.
Basically, the gist of it, as far as I get it, is this:
It's kind of Tolkien-esqu, with the classic races like Dwarfs and Elves, but darker and bloodier. It's not going for a beautifull fable or a mythical tale, it's far more down to earth. The main evil force is the Chaos gods, with their cults, mutants, spreading corruption, dark magic, etc. The "good guys" is the usuall set of Humans, Dwarf and Elves, but no one is really all that good. Especially the humans and their Empire are not really all that pleasant, at least unless you're a fan of the Inquisition, burning people at the stake and stuff like that. Wizards get much more fear than respect, and most likely everyone has some nasty agenda of their own. A lot of stuff is the familiar, stereotypical stuff- elves are best at magic, dwarfs love technology, Orcs are the go-to stupid evil henchmen. You have your undead, your dragons and your giants.
There are other human kingdoms than the medieval Germany-like Empire, there's Norska, where you have this worlds version of vikings, Kislev, which is sort-of Russia and Bretonnia, which is sort of a mix between medieval France and England from the Arthurian myths.
I don't think you'll need much knowledge of the lore for Total War, and if you do want it you'll likely get a lot of it fom wikipedia. But if you want to buy something to get more, I guess the core rulebook for Fantasy Roleplay will give you most of what you need, it has the rundown of the world's history, describes how magic works, and all such stuff.
Post edited December 11, 2015 by Breja