The Nightmare War (2006)

From publisher blurb:

The Nightmare War explores the desperate battle for survival in a near future earth. Possessing the form and memories of a human life and the elusive nightmares of a truly alien past, you must contend with a new life as something more than human.

A 'stand-alone' campaign sourcebook for players and games masters - pit your characters, cursed with a terrifying alien legacy, against malevolent forces intent on their utter destruction. In the world of 2035, the Nightwalkers struggle to survive and to understand what they have become; and just what it is that hunts them.

The Nightmare War illustrates a conflict fought in the shadows including in-game world information, five new character classes, dozens of feats & skills, new technology, antagonists & allies, over a dozen NPC classes, 6 new character sheet, and tools for running a single story or entire campaigns.