Prologue

       They were not omnipotent.

       Throughout their multi-million-year period of galactic dominance, they’d been known by many names. The Destroyers. The Hunters of the Dawn. The Enemy. The Xul. They called themselves by a thought symbol that might translate as We Who Are.

       Perhaps ten million years ago, give or take some few hundreds of thousands of years, We Who Are had possessed organic bodies; as such, they’d been a species, like all heirs of flesh, shaped and constrained by the impersonal forces of evolution. In common with all products of the evolutionary process, they’d possessed a marked will to survive.

       What most clearly distinguished We Who Are from most other species was simply the extremes to which that will carried them.

      Early in their history, they’d survived—barely—a traumatic encounter with another species upon their home planet. That encounter left them shaken, brutalized, and monomaniacally mistrustful of the motives of anything Other.

       It left the other species extinct.

      That ancient struggle for dominance, ultimately for survival, imprinted itself upon the psyche of We Who Are. When, in due time, they began moving out into the Galaxy, they carried that imprint with them. No other species posing a threat, however remote, to We Who Are could be permitted to survive.

       Over the course of some millions of years, We Who Are extended and expanded the range of their lonely suzerainty over the Galaxy. Eventually, however, they encountered the far-flung bastions of another starfaring species, nocturnal psychovores who styled themselves as the Children of the Night. Like We Who Are, the Children possessed as a racial trait the need to exterminate all competition. Unlike We Who Are at that time, perhaps eight million years ago, the Children were already ancient, their line extending back into a murkily remote past when they, in their season, had wrested dominance of the Galaxy from a still more remote species, a self-aware congeries of organic superconductors that called themselves the One Mind.

       Young, fired with righteous ambition and an instinctive determination to crush all competition in order to be alone, and therefore safe, within their Galactic fastnesses, We Who Are eventually triumphed after a savage no-quarters war that scoured a hundred thousand worlds of life. The Children of the Night passed into the ultimate Night of extinction, as had the One Mind before them.

       And with that victory, the We Who Are became the new xenophobically senticidal caretakers of the Galaxy.

      More millions of years passed. Eventually, like the majority of technically oriented species before them, We Who Are chose to discard their organic bodies, uploading their consciousnesses into nearly immortal cybernetic shells. They carried with them, however, the racial traits of mind and awareness that had distinguished them as organic beings—including the blatantly Darwinian imperative to eliminate all possible competitors, all possible threats to their existence.

       In fact, this radical form of natural selection had dominated the galactic scene ever since sentient life had first emerged, some eight billion years before. In any given epoch, it took only a single intelligent species with technic aptitude and a lack of empathy for anything Other to emerge from the cauldron of its birthworld and insure its survival by eliminating all possible rivals. Galactic civilizations rarely overlapped perfectly in terms of their scientific and technical levels; with each encounter, one species tended to be older than the other, usually by many thousands or tens of thousands of years, and hence far more technically advanced.

       As new civilizations emerged and achieved technical capabilities permitting space flight and long-distance communication, most wondered why the skies of their worlds, which should have been humming with the signs of advanced civilizations, seemed so silent, so empty. Each time new races, new civilizations took their first tentative steps out beyond the worlds of their genesis, We Who Are, sooner or later, detected their efforts from their scattered bastions, descended upon their worlds, and relentlessly exterminated them. Hence, the silent sky.

       But like the Children of the Night, the One Mind, and so many others who’d come before, We Who Are were not omnipotent. The vast, sprawling spiral of the Galaxy, possessing some three hundred billion stars, is far too large, with far too many worlds, for any one race to monitor every possible lifeworld, every emerging sentient species.

       And there were so