Kikou Shoujo wa Kizutsukanai, also known as Unbreakable Machine-Doll, is a Japanese light novel series written by Reiji Kaitou and illustrated by Ruroo. The story follows Raishin Akabane and his automaton Yaya as they participate in the Walpurgis Royal Academy of Machinart's combat tournament, seeking both strength and revenge. The series blends fantasy, action, and steampunk elements, and received an anime adaptation.