Annihilation Factor

From the Garlowe Clusters in the north to the Veils of Darkness in the south, the Star Kingdom sprawled over roughly a fifth of the galaxy. So huge was this realm that those who tussled for power over it seemed unable to appreciate that it faced annihilation by the Patch, a roving region of peculiar pseudo-energy a light-year across which drained the life-force from any living thing it encountered.
The Patch had moved into the Kingdom and was systematically feeding on system after system. Cynically unperturbed by the appalling loss of life, the royal houses merely tried to involve the Patch in their machinations, to the extent that civil war broke out all over again. But in the event, the Patch was to provide the crucial factor in the struggle for absolute power. The Annihilation Factor!