Your Magic Name Is Rina Witch: The Idol's Familiar

Story

The demonic spaces called 'Forbidden Zones' that suddenly appeared all over the world. The monsters that emerge from them, the Eaters, which devour the human spirit. Humanity was powerless against the Eaters, on whom any physical attack, even nuclear attack, has no effect, and humans whose spirits were devoured turned into Eaters one after another. But humanity is not powerless forever. The exploits of warriors who wield an attack technique using the biological energy called 'Mana'... magic, and who alone can defeat the Eaters. People called the warriors of humanity's hope witches... Only girls can use magic! Mana, the source of magic that every human possesses. But in men, most of it is discharged as sperm! What is the role of the useless man!? Witches too, through menstruation, lose large amounts of Mana and become unable to use magic. And so what was devised is Mana resupply via the sperm of men who harbor large amounts of Mana! Boys and girls pair up at the academy that raises witches! The 'Witch School', a fortress for humanity's defense run by the state. Upon enrollment, boys and girls pair up, and the man, as a Mana tank rather than a sperm tank, offers his sperm to the witch he's paired with! Mana resupply is a sacred act, so it's not embarrassing. At the academy, efficient Mana resupply = sperm resupply is taught! Sex is by no means an obscene thing. To fight the Eaters, boy-girl pairs must carry out sacred Mana resupply anytime, anywhere! The more pleasure the witch feels, the greater the efficiency of Mana resupply! Master every sex technique and pleasure-train the witches!