Supreme Casanova: Ultimate Harem System - Chapter 2: Crazy System!

It is the turn of the century and humanity has ignorantly stepped into the starry space to lay themselves bare under the eyes of gods. The young man Luo Nan bears the sins of his forefathers. He walks out of a laboratory and is seen holding burning notes up high, his feet treading on the bones of gods. A myriad of living beings are formatted in writing. Universes are added and deleted in the star records.

A failed investor from 2017 got drunk and woke up in the 1980s. China is just opening up, and the economy is blooming. There is also the dissolution of the Soviet Union, the bursting of the Dot-com bubble and other financial crisis. He used his knowledge of the future and slowly build up his empire.

- Description from novelupdates

Zhang Gong decides to learn light magic, a magic few show interest in and eventually becomes the legendary Grand Magister. While trying to end the continent’s east and west separation in order to unite all of the different races, he becomes every race’s Child of Light.