First to Fight: The Empire's Corps, Book 11 (Unabridged‪)‬

Before Avalon, before the Fall of the Empire, Edward Stalker was a young man growing up in Earth's Undercity - a nightmarish rabbit warren of tiny apartments dominated by gangs who loot, rape, and murder with impunity. When his family is killed in a gang attack, Ed takes the opportunity to run to the one place that will take him: the Terran Marine Corps. But becoming a marine isn't easy, and Ed will find himself pushed to the limits, surviving a training program designed to weed out everyone but the best before he learns what it means to be a Terran Marine....