Immortal Guardians12 books in series
Darkness Dawns Publisher's Summary
Once, Sarah Bingham's biggest challenge was making her students pay attention in class. Now, after rescuing a wounded stranger, she's landed in the middle of a battle between corrupt vampires and powerful immortals who also need blood to survive. Roland Warbrook is the most compelling man Sarah has ever laid hands on. But his desire for her is mingled with a hunger he can barely control...
In his nine centuries of immortal existence, no woman has tempted Roland as much as Sarah. But asking her to love him is impossible---when it means forfeiting the world she's always known, and the life he would do anything to protect.