the aliens are already here, in warp state by the millions in their city ships, the "cities of light". and cloning is a common practice and there is channellings to suggest they clone humans. they are steadly warping non-traditional religions and basically have their own 'theosophy'/religion - ascensionism. which is a social conditioning to control the majority of the population, which are both slaves or menials and cloned.
the psychological acceptance of being meant to suffer throughout however many clone lives makes for a good slave population.