Little, Brown Book Group Chained Soldier, Vol. 1

Decades ago, gates to an otherworldly and dangerous dimension known as Mato—the "Demon City”—appeared across Japan. Those who partook in the "peaches” growing there gained unique abilities—but only if they’re girls. When down-in-the-dumps high school boy Yuuki Wakura finds himself caught up in a gate, he’s saved by Kyouka Uzen, the beautiful commander of the 7th squad of the Demon Defense Force, who…orders him to become her slave?!