MTL - Full Marks Hidden Marriage - Chapter 5 Little Master found it.

The Devil’s Den was Cosette’s favorite webnovel that she had followed for three whole years. She waited for updates, wallow in those empty days during the author’s constant hiatuses, cry and laugh with the characters; it was already a part of her short life.

Cosette really wished that the novel would never end despite that she was terminally ill.

But after three years, The Devil’s Den finally came to an end. With a reader as invested as Cosette, she had mixed emotions about the ending. Not that the ending was disappointing, but what disheartened her was the ending of her favorite character; the villain Maxen Devilsin.

One year later, Cosette took her last breath only to wake up in the body of the stunning Cosette Blac; the villainess of the novel The Devil’s Den, her second favorite character after the villain.

Granted with the opportunity to live in the world of her favorite novel before the main story starts, Cosette had a plan.

That was to simp over the characters and save her favorite characters whilst hoping that the female and male lead still have their happy ending.

In a world that was already written and events that were expected to happen whether or not they wanted to, can Cosette change the course of their lives? Was overwriting the characters' fate could save them? Or would it just give them a much worse ending than what the author had given them?

Watch Cosette as she tried to become the superfan and give the dark-themed story some light.

However, he did not know that he was not raising just a harmless pet, but a biological weapon secretly made by the government… a real monster.

As a former librarian, Rand felt that he had been living an ordinary life, the one that he had reclaimed unconsciously every single day.

Recently, he has been a little upset because the pet fish he accidently brought home to raised seems to have undergo some strange changes

Well, it turned into a merman.

- Description from Novelupdates

She, Xue Fanxin, a famous medical genius in the 21st century, had transmigrated into the body of the dumb daughter of the Grand Duke.