Bloody Plum

For 2000 years they hid, silently building their empire, drip feeding religions, creating monarchs, funding governments of war to keep humans at each other's throats to keep them divided long enough to introduce technologies that create the perfect subservient society. when they revealed themselves everyone was so pre-programmed no one even noticed, and snap the earth was theirs. 200 years past with only a handful of humans still free of slavery, huddled together in the ‘freelands’ patches of land the invaders didn't feel the need to bother with.