Mato Seihei no Slave

Mysterious gates to a dimension called Mato have appeared across Japan, releasing dangerous monsters while the realm's Peaches grant supernatural abilities exclusively to women. When Yuuki Wakura is pulled into Mato, he is rescued by Kyouka Uzen, commander of the Demon Defense Force's Seventh Unit. Kyouka's power allows her to enslave a living being and draw out its strength, but nothing she has controlled before has been truly useful. Using it on Yuuki changes everything: his transformed body becomes an exceptionally powerful weapon. Kyouka brings him into the unit as her special servant, placing Yuuki between monster battles, domestic duties, and the unusual rewards her ability demands after every transformation.