I Became a Monk in Japan and Exorcised Demons of Other's Housewives - Chapter 45 - Time for a Cigarette!

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

The heavens and earth change when the blood phoenix descends.

Xiao Yu was humanity’s greatest genius, a scientist whose intellect surpassed all others. He saw the signs of Earth’s impending doom a decade before it happened, warning the world of the catastrophe to come. But instead of being hailed as a savior, he was ridiculed, dismissed as a madman by his peers, and ignored by society.Realizing that nothing could change humanity’s fate, Xiao Yu made a decision. He turned his brilliance toward survival. Using knowledge decades ahead of human science, he constructed the first true interstellar battleship—not for humanity, but for himself. And when the end came, he did what no one else could. He abandoned his mortal body, fusing his very soul with the ship’s central computer and escaping into the endless void.Now, drifting through the vast and indifferent cosmos, he is the last remnant of a dead civilization. But he refuses to let humanity vanish without a trace. Why was Earth destroyed? Was it truly unavoidable, or was there something more sinister at play? To uncover the truth, he must push beyond the limits of human science. His battleship is just the beginning. Through relentless technological advancement, he will evolve, forging a warship that can traverse the stars, a fleet that can reclaim humanity’s lost legacy.The universe is vast, filled with unknown civilizations, ancient mysteries, and dangers beyond imagination. But Xiao Yu will not stop. He will find answers. He will ensure humanity’s flame is not extinguished.The journey into the unknown begins now.