Valkyrie Smash - Chapter 102 Sixty Nine.

What happens when a man gets transported into a foreign world filled with magic?

He is the ruler of the mercenary realm, an overlord that gives headaches to the leaders of any country! For the sake of his friends, he’s willing to sacrifice himself; for the sake of his family, he does not hesitate to spill blood! He is a dragon, one that soars above even the highest of heavens. He’s a power that advances triumphantly through unstable situations, stirring up both the winds and the waters.

- Description from Novelupdates

“Dafeng Night Watchman” tells the story of modern policeman Xu Qian'an who traveled to the Dafeng Dynasty. As soon as Xu Qian'an traveled through time, he was involved in the case of the loss of his second uncle's tax silver. He was later implicated and imprisoned and faced exile, but he successfully solved the case with his past life experience and wisdom, rescued himself and his second uncle's family, and joined the night watchman organization. After that, he encountered various murders, political struggles, and entanglements with mysterious forces. He killed his superiors in anger to save the female relatives of the prisoners, was involved in the Sangpo case, participated in the struggle between Buddhism and the Kingdom of Ten Thousand Monsters, and entered the sight of major forces. In the end, Xu Qian'an realized that his mission was to plead for the people and protect the weak. He began to run around for the people of the world, promoted the alliance between Dafeng and the Southern Xinjiang Gu Clan and the Kingdom of Ten Thousand Monsters, and joined hands with Princess Huaiqing to launch a coup to save the people of the world. The novel combines a variety of cultural elements such as Confucianism, Taoism, Buddhism, the demon clan, and sorcerers, showing Xu Qian'an's intelligence and detective skills.

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