Mato Seihei no Slave

When entrances to a different dimension known as the "Mato" emerge all over Japan, a new resource known as "Peaches" are discovered which give unique abilities only to women. However, dangerous monsters called "Yomotsu Shuuki" also roam throughout the Mato and have been responsible for various disasters ever since. To combat the Yomotsu Shuuki, the government formed the Anti-demon Corps, an elite group of women who have received power from the Peaches.

One day, a high school student named Yuuki Wakura was walking home from school when he suddenly gets lost in a Mato entrance. When he calls for help, he is immediately rescued by Kyouka Uzen, the chief of the Seventh Unit of the Anti-demon Corps. Recognizing his potential while also needing him to make her Peach power more effective, she ask that Yuuki join the Anti-demon Corps by becoming her slave, a position he might find more enjoyable than he initially would have thought..

(Source: MU)