Life, Once Again! - After Story 187

Abandoned at birth in a humble stable, Shirone was raised by commoners—but he was anything but ordinary. Blessed with remarkable insight, he taught himself to read at a young age. A fateful visit to the city introduced him to the wonders of magic, igniting an unshakable dream of becoming a mage. Yet, beneath the city's dazzling facade lurked a ruthless social hierarchy, where power and privilege crushed those who dared to rise above their station. As Shirone uncovers the world's darkest secrets before even coming of age, one question remains—can he defy fate and claim his destiny as a mage in a world determined to keep him down?

Lin Fan acquired the Sign-in System that led him on the path of the life of a god-level nouveau riche.

Discovering that his wife was cheating on him with his superior, Jonathan Hayes was put on the combat list by his superior, a list that had already been concluded weeks ago.Wanting to survive from the war and come back to get his revenge on his wife and his superior, Jonathan was killed in the battlefield.Instead of going to heaven like every good man should, Jonathan woke up five years back in time, before his country was captured by the enemy, due to the help of his country's corrupt leaders. Jonathan knew his job immediately he realized what had happened to him. To liberate his country from getting captured again, and to get his revenge on his cheating wife and his superior.He had guessed correctly, but there was more to it. He not only went back in time, he woke up in a parallel world where magic was present. His job was not only to rescue his country from getting captured again, his job was to become the first warlord of the world. The first king of the whole world.[Congratulations, you have been rewarded with two unique skills from God]

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates