Hengoku no Schwester

Is the "Iron Maiden" an ancient torture device fashioned after the likeness of the Virgin Mary? With its interior punctuated by razor-sharp spikes, those trapped inside would meet their demise in a gruesome and agonizing manner. However, the version of the "Iron Maiden" that exists today is nothing more than a fabrication modeled after historical lore. But who is this "maiden" with a countenance of compassion and a body of ferocity? Could this infamous device have truly existed in the past? This is her tale.