TheAnvil of Dust and Stars

This is book #1 in my Dark Seas book series. In this book my hero for the series is born, Sarah Dayson. She rises to become a powerful military fleet commander. Her efforts are critical in saving humanity from an enemy of our own creation, the Hive. They are nanomachines that conquer human planets one at a time adding the human captives to a Hive mind by infecting us. Sarah finds in the end that saving humanity doesn't need to mean an epic battle.