The Demon's Guidance

A wisp of a demon's remnant soul guides a special forces soldier who accidentally arrives in this world onto the path of cultivation. Under the arrangements of the demon lord, he gradually embarks on a path of confrontation with the celestial emperor. After enduring hardships and teetering on the brink of life and death, he realizes that the heavenly way is flawed, ultimately defeating the celestial emperor and the demon lord, and returning home.