Saving the Villain: the Demon King's Beloved

Introduction: [No heroine + Book-traveling + System + Funny] Jun Yichen accidentally entered a book he picked up on the roadside, and the book unexpectedly bound his identity. Take care of what you have come, in line with the philosophy that if you have the system in hand, you have everything in the world, but who knows that this system is not a fuel-efficient lamp and always breaks down every time something goes wrong. Jun Yichen held up his forehead: "How many lifetimes of bad luck did I have to suffer before I encountered this sixth system!" ——If the system doesn't work, then I'll work on it myself. Don't panic when you encounter a big devil, just face it and you'll be fine. Vice versa