GURPS Black Ops (1997)

Wrestle enraged gargoyles on rain-slick ledges high over dark city streets! Endure the raw psychihc fury of the dreaded soul dog! Above all, watch out for the insidious Greys, as they kidnap human woman and steer the destiny of entire nations!
Our only defense against these terrifying foes is the Company, which takes conspiracy from theory to practice. As one of its recruits, you'll endure five years at the hellish Academy, where only the best of the best graduate and failing grades become tombstone inscriptions. Upon become a black op, you'll possess attributes and deadly expertise to make mere mortals tremble.
You'll need them - because it's all true. Ancient alien visitors and recent arrivals, things slithering in sewers and alleys by night, dark plots by paranormal cabals to bend humanity to their will - all these dangers and more lurk in society's shadow.
Odds are you'll die in style. Your job is to take as many of them with you as you can.