Rise of the Undead Legion - Chapter 18 Rank Up!

In a world fractured by conflict and haunted by shadows of the past, Kokushibo—the first Upper Moon demon—meets his end, only to awaken in a new life. Reincarnated as Crimson, a child born into a different family, he carries the memories of a past he cannot escape. Burdened by centuries of guilt yet indifferent to the present, he resigns himself to duty—until an unexpected bond with his newfound family begins to thaw his hardened heart. As he struggles between the weight of his past and the weight of the new life, Crimson must decide whether he will remain shackled to his former sins or embrace the possibility of peace.

This is a story of a little man who walks forward silently, in awe, and strives to chase his dream.

- Description from novelbuddy

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

When the eldest prince Luo Fei reached 18 years old, the database automatically screened the genes of omegas across the entire empire for matching. The only son of a wealthy businessman, Mo Lin, had a gene match of more than 90% with the eldest prince. However, the moment he saw Mo Lin, Luo Fei learned that this omega is a sick child with paralyzed legs, hemiplegia, and severe mental illness???