Maoyuu Maou Yuusha

A Hero arrives at the Dark Lady's castle seeking to confront her, only to be asked for assistance instead. He recounts the devastation caused by the demon-led war, which has led to countless deaths and suffering among humans. The demon queen counters by asserting that the war has unified human society, citing evidence of population growth, increased productivity, economic gains, and societal improvement. She warns that ending the war could lead to a civil conflict with even greater bloodshed. Convinced that continuing the war is the lesser of two evils, the Hero agrees to support her plans in pursuit of what he sees as a more stable peace.