After backstabbing the villain, the system allowed me to enter the book again

Du Mingxing transmigrates into the role of a vicious supporting character. To correct the book’s ending and prevent the villain’s destruction, she plays the role while fulfilling the system’s mandate to heal the future, the ruthless villain Shen Chumo. Ultimately, she stabs him in the back, having completely surrendered to her.
After completing her mission, she returns to reality. The system’s multi-million dollar bonus arrives with a ding-dong sound, but she stares at her pristine palm, as if stained with bl00d.
The real world falls silent, and her life returns to normal. However, one night, the vanished system issues a piercing alarm: “Small world deviation value too high, no longer detectable! Host, please transmigrate again!”
Du Mingxing: “…it’ll cost more.”
Upon her second transmigration, everything has changed. The once-high-rise building has been reduced to ruins. Betrayed, the villain, as envisioned in the book, turns evil and destroys the world.
The boy who used to pretend to sleep, letting her play a trick by tying his shoelaces to death, now looked like he had returned from hell. He opened his eyelids, his eyes icy cold, and the black mist on his fingertips turned into blades, piercing her chest with cold air. In an instant, a dazzling bl00d flower bloomed on her heart.
Du Mingxing was silent. When they met again, she was killed by a single blow before she could even open her mouth. He actually hated her so much.
After a while, the bloody hole in her chest slowly closed and solidified again, as if she had never suffered a fatal injury. Du Mingxing was confused, watching him slowly close his eyes, his brows furrowed.
“Another… inner demon.”
“The ghost lingers.”
It turned out that he had developed an inner demon because of the backstabbing.
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Shen Chumo once had a nightmare in which he was abused by the girl in his dream and called a monster. Contempt and hatred were revealed in her almond-shaped eyes without any concealment. But when he woke up, he saw that the other party was hard-mouthed but soft-hearted. She was obviously doing it for his own good but pretending to be a villain.
He was sure that this was her.
Until the dream and reality overlapped, and he was injured in the abdomen and back, he turned around and saw that familiar pretty face, with the same expression in the dream, smiling sweetly and uttering cold and coquettish words,
“Monster, it’s better for you to die.”