The Harvest Mouse Exits the Fairytale Together with Cinderella - Chapter 22

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

Leon was once an ordinary man—until he died saving children and woke up in a new world as the last prince of the demon race. But his awakening comes with a cruel truth: the war is already over.The Demon King is dead. The once-mighty demon empire lies in ruins. And now, Leon stands amidst the ashes, surrounded by a handful of survivors teetering on the brink of extinction.Crowned Demon King by default, he holds the title—but there is no kingdom left to rule. The few remaining demons are barely surviving, hunted and outnumbered. Worse still, Leon, who once enjoyed the luxuries of modern technology, must now navigate a harsh world stuck in the Middle Ages.Can he pull the demon race out of their misery? Can he reclaim the power they once held? Or will history remember him as the last king of a fallen race?Follow Leon on his journey to rebuild, conquer, and defy fate itself.

I dedicated 10 years of my life, focusing solely on regression.[Authority: Death Regression has naturally been nullified.

Synopsis: Yang Chen, the inheritor of the divine throne of Hades, was separated from his family at a young age and sold to a foreign assassin organization. Enduring the darkest of worlds, he eventually returned to his homeland incognito. Intending to live a low-profile life as a street vendor selling lamb skewers, fate took an unexpected turn when he married a well-known local corporate CEO. Hoping for a quiet existence, he found himself drawn into the role of a guardian knight due to the presence of beautiful women from various walks of life. As he navigates through these connections, his past experiences and former comrades resurface. Inadvertently, he delves into the world of cultivation in China and uncovers the essence of this world.