If you heard the title Fallen Angels and knew nothing about this book, soldiers in the Vietnam War just might not be your first thought. A religious book, maybe, or a paranormal story about sexy demons fighting.
When the word angels first shows up in the story, it's in a prayer that Lieutenant Carroll says over the first soldier Perry sees die: "Lord, let us feel pity for Private Jenkins, and sorrow for ourselves, and all the angel warriors that fall." (4.19)
When Perry asks Carroll why he referred to Jenkins as an angel warrior—kind of weird to call a down-and-dirty soldier who's trained to kill an "angel"—Carroll explains, "My father used to call all soldiers angel warriors…Because usually they get boys to fight wars. Most of you aren't old enough to vote yet." (4.20-21)
So he doesn't mean angel as in holy, exactly. He means angel as in young and innocent, like how your cheek-pinching grandma might call you her little angel. But in this case, the threat of gruesome death is hanging over you, so not exactly a trip to grandma's.
Unfortunately, Private Jenkins isn't the only one to die. Soldier after soldier bites the dust in this book. A huge part of the story is about how Perry, or any of his friends, could die at any moment. One man gets shot by a sniper while in the supposedly safe area of their hooch. Another gets killed by holding a child who's been mined. It's not pretty.
"Fallen" has another meaning, though, especially when connected with angels and religion. Sometimes, to fall means to have sinned. And these guys are definitely killers. Both Perry and Lobel have moments where they shoot a man they can see up close and personal, instead of some shadowy figure in the distance, and watch him die. No matter how much they're trying to get their side to win, it's not easy watching other humans die. Especially if you killed them.
Our author, Walter Dean Myers, isn't known for clear morals or easy answers. He's not saying these soldiers are bad, or good. Only that they're young.