The Last Commander

After ten thousand years of war, humanity has obtained its wish—crusading the Milky Way. My name was Argo Herrero. I'm now Lynx, my code of war. Planetary system after planetary system, we've slain all intelligent species once alive in our galaxy. All but one, the last intelligent species left to be purged by our ranks.
What will become of us when we've purged the whole galaxy? I don't know, but I'm afraid of what we'll become, of what I've already become.