Night Watch: Book One in the Night Watch Series - Sergei Lukyanenko

Blurb:

They are the "Others," an ancient race of supernatural beings—magicians, shape-shifters, vampires, and healers—who live among us. Human born, they must choose a side to swear allegiance to—the Dark or the Light—when they come of age.

For a millennium, these opponents have coexisted in an uneasy peace, enforced by defenders like the Night Watch, forces of the Light who guard against the Dark. But prophecy decrees that one supreme "Other" will arise to spark a cataclysmic war.