Read manga: Awakening In The Three Kingdoms As The Demon's Granddaughter ~The Legend Of Dong Bai~

manga
Summary:

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 granddaughter of the infamous tyrannical Dong Zhuo, Dong Bai. In order to avoid the fate of being executed alongside Dong Zhuo, Dong Bai will have to use both experience as a Japanese businessman as well as knowledge of the era!