Toaru Majutsu no Index - Volume 21, Chapter 5: The Complex Game Board that is a Battlefield. Enter_Project.

He said I was the most despicable woman he ever met…

In order to love him, I lost my family, and become an imprisoned tool used for his vengeance from a noble lady. Everyone said I was the daughter of a rapist… I cautiously maintained the excruciating deep love for him and suffered from mental and physical exhaustion…

I thought someday my love would touch him and then I would live a happy life just as a fairy tale, but in fact I fell into an eternal nightmare…

A young man with an extraordinary mind is off on an exciting adventure when he mysteriously wakes up in the body of a feeble slave-guy in a different, rich in quirks world.

The main character, a selfish jerk, would use extreme means to achieve his goals. However, he never allows his base instincts to overrule his sense of decency. He always pays back both good and bad deeds.

Will his (terrible/excellent) mentality help him make a fresh start? Will he get through misfortunes and hardships of the new world?

Yu Zhengdu joined a small start-up company that claim to offer “life management services”……as a programmer.

On his first day in office, he received a phone call from a stranger: “Hello, I received a text message from your company that informed me of my reincarnation tomorrow……”

Yu Zhengdu: “……??”

Shang Que, the beautiful little boss, said, “New employee, welcome to the Hell organisation in the human world. A thousand years ago, I was known to the human world as the Ghost King of Luofeng Mountain.”

Yu Zhengdu: “……??” From then on, he was incredibly distressed about the development of Hell.

- Description from Novelupdates

The world changed the day that cracks appeared in the sky– suddenly monsters named『Demonic Beasts』appeared and began to rampage, attacking people.

Meanwhile, girls called『Magical Girls』began to appear to counter the demonic beasts. As they defeated the demonic beasts, gradually people’s lives gained a semblance of composure.

–but when there is light, there is also darkness.

In the corner of an alleyway, a boy who had been attacked by a demonic beast was dying. His voice begging for help did not reach anyone and his body refused to move.

「Boy. Do you want to be saved?」

Looking into the boy’s face, a black cat began to speak to him.

The boy nodded firmly to the devilishly sweet invitation, in response the black cat mocked him.

「Is that so—then I’ll【Haunt (Save)】you」

—on that day, a『Magical Girl』was born in a place that no-one knew.

『She』never laments, no matter what the future may bring.