I Overcharged Every Weak Mecha Maiden

Every woman in this world can shift into a mecha form. Some come out as heavy armor, some as missile carriers, some as artillery, some built for flight, and one is a super-heavy carrier. Men have no combat form of their own. They serve as boosters, and at high enough synchronization they can push a partner into her full war-maiden state. Mu Chen wakes a rare core called the Heart of the Galaxy, which makes him a booster of a class nobody expected. The first person he links with is his own teacher, a woman known for being cold and distant in class, and the surge turns her into an iron war goddess. Others follow: the top student in his year, who carries a double transformation, the gunner whose fire never seems to run out, and the carrier girl. He can also raise damaged mecha-girls back to fighting strength. Then a beast tide arrives in numbers past counting, and the city defense turns into a wall of gunfire. Ordinary school days keep running alongside it, so classes and formations trade off, and the fight pushes outward from the city toward the stars.