Naruto: Paws and Whiskers - Chapter 74

The simulation is over, and the entry is obtained: a showdown!

Looking at this entry, Zhao Meng was stunned.

“How should this term be used?”

“Hey! Here’s a wounded fox!”

…

A few years later, a woman who looked like a fairy appeared in front of him, and said:

“My lord, I’m here to repay my favor!”

This book is also called “Starting from Transforming Monsters”

- Description from novelbuddy

Blayn transmigrates into the world of Akame ga Kill and obtains the Mangekyō Sharingan—Kamui! Not just one, but both Kamui!

Light?It was always something we depended on to see within the world but that has changed. What is one supposed to do when the world is engulfed by darkness?Giving us no choice but to adapt to the world we once knew. People turn into monsters, light ceases to exist, and yet I'm left here with no idea on how to move forward.I'll never forget the woman who gave me that direction to follow.A woman with beautiful long white hair, shining brightly under the moon is all I can remember. “Rise above them all. Become the strongest and you'll never have to fear the dark.” her voice echoes.I'll become the strongest... If that's what it takes to survive this hell.

Descent of the Phoenix – 13 Years Old Princess Consort

The strongest female assassin from a special assassination force met her death one day on a mission. To her surprise, she woke up in the body of a 13 year old girl, Mu Rong Liu Yue. Through Liu Yue’s past memories, she found out that she was bullied due to the huge birthmark on her face, even though she came from a renowned family. Liu Yue was beaten to death by her own cousin, and that’s how she managed to enter Liu Yue’s battered body. The assassin then decided to live her life as Liu Yue and swore to avenge her death.

- Description from Novelupdates