Substitute Bride Phoenix, The Tyrant's Pampered Demon Empress - Chapter 6: Making You Faint From Anger

To reward Meng Fan for his bravery before his heroic death, the cosmos rewarded him with a ‘system’, sending him back in time to three months ago, alive.

- Description from Novelupdates

An Individual from Earth finds themselves in the Shinobi World, equipped with a Scientific System. From that moment, he delved into scientific research far ahead of its time.

A surgeon accidentally got the blessings of a system, shocked the medical industry, and rejuvenated countless people.

- Description from Novelupdates

It was a time where demons roamed the earth and chaos reigned. The story took place in Luoyang, the legendary capital of the times. During the night, one could find people holding on to their food with dear lives as they faced off against stray dogs, people with weapons in hand vowing to fight against Fate to their very last breath. There was bloodshed everywhere as some died meaningless deaths, while the strong tyrannized the weak and the truth was frequently hidden. Some of the citizens had completely lost their mind, while some died on their travels. Most importantly, the words of a certain youth caused much panic in the human world. It was a time of little warmth as nights in the capital were frequently accompanied by gusts of wind and rain, and it would be covered with snow during winter. Such were the days…

- Description from Novelupdates