The NPC sets out to defeat the demon king - Chapter 18

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

Defiance of natural order of a single young Dragon soul.

This legend tells the tale of the protagonist, Kuroki summoned to protect the demon king from the hero.

Kuroki, unbeknownst to him, suddenly came to another world. He was summoned by the demon king, Modes. The territory which the demon king overrules was in the midst of being destroyed because of the hero. He had no choice but to bow before Kuroki.

“Please save us, Savior Dono!”

Kuroki nodded, deciding to save the demon king due to an unexpected turn of event.

“As a firearms modifier, it’s normal for me to have better marksmanship, right? John Wick?” —— “The John Wick Series”

“As a private detective, it’s weird to solve the case faster than you, and better than you can fight? Zhou Xingxing?” – “Play Back To School”

“As a psychiatrist, shouldn’t the patients in Arkham Asylum listen to me? Bruce?” – “Batman”

“As an archaeological expert, a little knowledge of Feng Shui and tomb chambers, isn’t this a basic professional quality? Wu Tianzhen?” – “Tomb Raider Series”

“As an animal breeder, is it too much to keep some Godzilla and King Kong?” – “Monster Series”

 …

One world, one profession, let ordinary professions glow with new brilliance in the heavens.

- Description from novelbuddy