Destroyer

Mankind's outer colonies are disappearing. Without warning. Without a trace. Fleet command chalks the attacks up to pirates, but Captain Dryker of the UFC Johnston isn't buying it.
Defying command, he leads his misfit crew into hostile territory in search of answers. They encounter the mythical Void Wraith, an unstoppable legend whispered by the first race. After 26,000 years the Void Wraith have returned to begin the next Eradication. Their technology is superior, their motives unclear.
Humanity cannot stop them. Not without help. Captain Dryker's only hope is to forge an alliance with mankind's greatest enemy, the savage Tigris.
One maverick captain, an unlikely crew, and an aging vessel are all that stand between humanity and the Eradication.
"It's like Battlestar Galactica and Mass Effect had a baby, and that baby was raised by Starcraft. I read this book in one sitting, and immediately looked for the next."- The author's totally biased friend.