Local Netizen Elf's Life In Another World - Case 8: Precision.

One rule: Survive. Everything else is optional.Reika Kagetsu doesn’t want to be a hero. She just wants to feel—pain, fear, adrenaline—anything to remind her she’s still alive.Tenshiko Academy promised her that.What she got instead? Brutal training. No rest. No second chances. And monsters—inside and out.Now she’s fighting the Shikiban: creatures born from blood, madness, and buried secrets. But the deeper she goes, the more she begins to wonder...What if she’s one of them?Power always comes with a price. And Reika is about to pay it in full.

He is high above, the mysterious and terrible King of the Wild. With one glance, he can see people’s romances. He hates women to the extreme, but at his first glance of her, he dotes on her and spoils her.
She is a humble transmigrator, a miracle doctor who doesn’t care for the many handsome men around her. She only wants to become strong, to be worthy of that god-like man. But when she’s finally sure of her feelings, she finds out she’s already been married for years…
……
When wronged：
She uses strength to hit the big handsome iceberg-like man in front of her eyes. “People say that I’m not good enough for you, but it is you who is an old cow eating tender grass!”
A man seizes the main point and laughs like an evildoer. “This husband has to eat the grass to confirm if it is tender or not!” He puts out the red candle……
……
The world says：
The barbarian king has no heart and has no passion.
A pregnant woman very miserably thinks,” If he has no passion, then who is responsible for this big belly?”

- Description from Novelupdates

Framed for something she did not do which resulted in her only son’s death, she was abandoned by her husband. Reborn after an accident, the eighteen-year-old Ye Tianxin swore to reclaim her life. Then, due to an unexpected twist of fate, she saved the life of a powerful man and her new destiny was rewritten!

Even after knowing what came next....I still accepted.A deal with the devil herself.A devil, in the form of a goddess.I accepted a life that I knew wouldn't end well, a life that was worse off than the very curel one I already lived.But I still choose to do it.I chose to become the villain.