Black Dagger Brotherhood

The Black Dagger Brotherhood is an ongoing series of paranormal romance books by author J. R. Ward. The series focuses on a society (the "Black Dagger Brotherhood") of vampire warriors who live together and defend their race against de-souled humans called "lessers". The first book in the series was published in 2005.
Ward's Fallen Angels series is set in the same universe, and has some overlap in characters, but little overlap in story lines.
Black Dagger Legacy.
A spin-off series that details the trainees. 
Fallen Angels Series.
Series set in the same universe, but takes place in an earlier timeline