I'm 90 years old and the system tells me it's time to create harem - Chapter 1: A system sixty years too late

Youth, is meant to be used to shed sweat under the sun!

Youth, is to continuously engage in battles, and secure the win! The endless journey on Heaven’s Road, an endless expedition, a testimony of a hot-blooded youth’s legend!

A dream every man harbors, with the ignition of the blood! Forever young, Undefeated God of War!

- Description from Novelupdates

Hundreds of years ago, Human, Celestial Clan and Demon Clan lived together on the Origin Continent. However, a great war broke out between the three races. Shan He, the leader of Human, had discovered a catalogue of methods to forge Divine Weapons. With this catalogue, Shan He led Human to defeat the other two clans and expelled them from the Origin Continent.

The peace did not last long. After the passing of Shan He, the once Glory Empire collapsed. Various forces of Human fell into a long period of wild war for the Divine Weapon Catalogue, but the catalogue was lost during the war.

The Demon Clan took advantage of the internal strife of Human. Under the lead of their new lord, Fen Tian, the Demon army invaded the Origin Continent violently.

Human soon lost a large portion of their territory. At that moment, a mysterious hero suddenly appeared on the battlefield. With a legendary Divine Weapon in hand, he severely injured Fen Tian and forced him to retreat. The united Human army chased the Demon army across the strait and to the Two Realm Plain on the Tranquil Continent.

Once again, the various forces of Human started wildly searching for the Divine Weapon Catalogue…

- Description from Novelupdates

Rainer, an amateur arcanist and college student, sought to create a new spell far surpassing the magic of the few he inherited from his grandfather. Yet the interference of an unknown event during the casting of his spell led him to be thrown through space and time.

As a Beta, Ning An’s goal in life was to work hard, make money and get rich. However, his own dear father changed his aspiration and made him become a military academy student. Initially, he wanted to spend his days lazing about. What? The first place in the year gets a generous scholarship? Then staying up to study and train my body is nothing at all! The first place scholarship is definitely mine!

The A in the opposite dorm: So you’re actually an O.

Ning An: Ah?

The A in the opposite dorm: I know. You’re risking it all to prove that an O is not inferior to an A.

Ning An: You know my ass. Laozi is a B.

The A in the opposite dorm: You need to correctly recognise your own gender ah.

Ning An: …. Teacher. Report. I’m afraid this person is stupid.

note: Pretending to be a B’ is 装B (Zhuang B). 装B also means to boast or show off

- Description from Novelupdates