Youjo Senki, also known as Saga of Tanya the Evil, is a Japanese light novel series written by Carlo Zen and illustrated by Shinobu Shinotsuki. The story follows Tanya Degurechaff, a ruthless salaryman reincarnated as a little girl in an alternate war-torn Europe. With her strategic mind and magical prowess, she climbs the military ranks in a bid to defy Being X, the mysterious entity responsible for her reincarnation.