First Contact — Michael R. Hicks

In the first book of the In Her Name: The Last War trilogy, the Terran survey ship Aurora makes a startling discovery in an uncharted star system: two planets inhabited by an advanced, and decidedly unfriendly, non-human civilization. Disabled by gigantic alien warships before it can escape, the Aurora is boarded by nightmarish blue-skinned warriors with claws and fangs who slaughter the crew in ritual combat using primitive weapons. The sole survivor, Midshipman Ichiro Sato, is returned to Earth as a messenger bearing a device that warns of an impending attack.

For that is the way of the Kreelan Empire, which has waged war against civilizations across the stars in its quest for a savior, one not of their own blood, foretold in an ages-old prophecy. With only a few generations left before their ancient species faces extinction, the Kreelans will wage their last war against humanity, hoping against hope for redemption of sins long past.

If you're new to the In Her Name series, here is the author's recommended reading order:

1. The Last War Trilogy

• First Contact
• Legend Of The Sword
• Dead Soul

2. The Redemption Trilogy

• Empire
• Confederation
• Final Battle

3. The First Empress Trilogy

• From Chaos Born
• Forged In Flame
• Mistress Of The Ages

Note that The Last War and Redemption have also been published as trilogy collections.