Tim e travlors the last rapture book two.: mutant war sagas

This book details an alternate world similar to ours, a world whose surface is about to be devastated by something we can't land on, blow up, or spit on to stop it from nearly wiping out all of humanity! a world where it wasn't gods, angels, or prophets that came to our rescue, but the very being we have been taught to fear. It was an alien who came to destroy us. It was from another solar system.