Its been a few years( like 15) since I read it. What I remember is aliens take over the planet and enslave humans to build a tower/ structure that will protect them while they reproduce. The aliens scientists use genetics to increase reproduction from one to three. There is also a character called three eye or third eye( called this because he was shot in the head with a dart but it didnt blow up, leaving him a scar). The resistance is planning on attacking the aliens while they reproduce. I cant remember much more beyond this. Any help would be greatly appreciated. And tia!