The Chosen — Shay West

Astra. Kromin. Volgon. Earth. To each of the four planets are sent four Guardians, with one mission: to protect and serve the Chosen, those unwitting champions of prophecy who alone can save the galaxy from the terrifying Mekans. But the signs of prophecy have not yet appeared, and the decision to send the Guardians early could doom all in the galaxy to death.