@ArdainianRight Read Xenocide by Orson Scott Card to learn why that's a bad idea.
@ArdainianRight A tribal alien race is converted to Catholicism by the human colonists. This alien species depends on a virus in order to reproduce, but the virus is deadly to humans. The alien species is also able to live pretty much forever because they can "die" and turn into a tree. So they think they are morally superior to humans who are cursed with original sin and actually believe that they were chosen by God to bring Judgement Day so they attempt to hijack starships in order to spread the virus to other human colonies.
@ArdainianRight They wanted to wipe out ALL of humanity. Humanity also previously genocided a different alien species, so it is believed that humans aren't just sinful but downright evil and God doesn't forgive them.
@KryptoBlok @ArdainianRight It's a sequel to Ender's Game and Speaker for The Dead. Make sure to read those first.