Touhakuden: Maou Reijyou kara Hajimaru Sangokushi

Shirokawa Sasane (30) is a former trading company employee and a huge fan of Romance of the Three Kingdoms. One day, after losing consciousness in Chinatown, he wakes up to find himself in the form of a little girl. However, the new body he finds himself in isn't just any little girl, but the daughter of the infamous tyrannical Dong Zhuo, Dong Bai....