Goddess Medical Doctor - Chapter 13

What if Magic has always existed ever since the beginning of the Earth we are living on, but history has been written in order to hide these facts. What if the prosperous and well-known people in history is actually a mage?

Enter a magic academy, rule your country. Be at the pinnacle of life! Join me in the journey of Emery and the others in the world of Knights and Magic as he becomes the Earth's Greatest Magus.

In the twenty-ninth year of the First Emperor, Bo Langsha was attacked.

When Ying Zheng merged the memories of the 21st century history doctor, looked at the mighty mountains and rivers in front of him, and said to himself, “In this life, my Daqin can’t die!”

- Description from novelbuddy

Luo Qing Chen is a wandering spirit that died thirty thousand years ago, roaming the Chaos Space

In order to not turn into dust, she is bound by an ice cold system to travel through time and space to complete missions.

Girls that pretend to be weak?  Slap them without explaining.

A silly cannon fodder?  Helping them amass treasures.

Meeting a real male god?  All of them will pamper.

System: Dear masters, what do I do if my host even dares bully the heavens?  Waiting for an answer, it’s urgent!

A certain male god: Change systems.

System: ヽ〔?Д?〕丿

An alien race invaded the Earth on June 6, 2128. At the midst of this war, many nations allied with the alien threat and the war nearly wiped out the rebelling humans of the planet. At the edge of mankind's survival, the United Nations Army launched its forces to eliminate the immediate stellar threats that loomed over Earth.

General Seeker Carlean, commander and leader of the mission, risked and gave his life to destroy the immediate stellar threat. The battle was won though Earth lay in ruins. Perhaps mankind will live to see a few years of peace before the alien threat returns to wipe out their existence.

At the immediate aftermath of the stellar battle, the fallen Seeker Carlean awakens and finds himself at aged 17, living the peaceful life he lived 16 years before he died.

So begins a new game in the battle for humanity's survival.