I might just add that the history of modern Blood Elves started many centuries ago when they split (or were cast out, if I recall correctly) from their "night" brethren... and it also had to do a lot with their magic addiction...
Elves are a twisted race... do you know that naga were actually elves as well? Their queen-goddess, Azshara was a Highborne...
I recommend
WoW Wiki as a good source, lots of good reading collected there.