Naruto: Dual-Pupil Uchiha - Chapter 1 : Monster??

Oscar, a destitute young boy, died in a tragic accident and was reborn in the forgotten realm. As a member of the lowly Birch tribe, his solace comes from the fragments of a guardian's spirit, residing in his soul. After the decimation of his family in the hands of a powerful race known as the dreads, he embarked on the part of revenge, leading him to the path of transcendence.

Betrayed by her entire family, Tang Yue, the seventh princess of the snake clan, was betrothed to the tyrannical Elven prince, who is known for his blood lust and cold-blooded murders.He is even rumored to have killed several concubines mercilessly.Deemed as a piece of useless baggage and now tossed aside as a political chip, Tang Yue braved herself for the new torturous life that awaited her.As if this was not enough, someone mysteriously poisoned her in the betrothal ceremony.But akin to a slap in the face, that poison actually turned around Tang Yue’s pathetic life!!Poisonous fruits? Sure give me some. I need to snack anyways.Deadly toxin? Sure. My throat is a bit parched.Heh. Now you want to actually cut me down? Sure. You just have to slash past this thick skin!The lowly beast that had invoked its innate ability to evolve silently resolved to conquer the heavens. And of course, she had a master... ahem... system to help her along the way!

The big guy dresses up as a lonely and old male supporting character, slaps his face and abuses scumbags to fall in love.
small world:
A scumbag male supporting actor who is lonely and old: learning to love with both hands.
The tyrant male supporting role who left the inheritance to the heroine’s son: the family has the throne to inherit.
The deposed prince: what kind of emperor, when the emperor!
Bingshan ex-husband of a book girl: It is impossible to chase after a wife.
The prince of the enemy country who retreated for the heroine: step on the capital and rule the world.
The pet girl mad demon of the group pet text: I pet myself.
Edible Guide: Quickly cross the routine, capitalize the romance! One cp in one world, if you change the world, your feelings will be eliminated. If you don’t like it, don’t enter. 

Content tags: face slap
Search keywords: Protagonist: Dongchen ┃ Supporting role: My concluding article “The Male Protagonist Doesn’t Follow the Plot [Quick Pass]” “Someone Wants to Take My Gold Finger [Quick Pass]” ┃Others:

- Description from novelbuddy

Gu Bai always believed that the stupidest thing he had ever done was listening to his bestie’s words of becoming a stallion genre novel writer, the most frustrating thing was that he changed the moral, smart, and healthy youngster, that he had decided on, into a big boss…but in the end, he discovered that the consequences of changing the original plot were more serious than he expected. Things like encountering the outrageous character he wrote with his own hand…

Oh·my·god! He freaking eats people! Right now, he can only turn devouring people into “devouring” people… maybe.

In short, this is a story about a dumb author who was the first to start a trend of human cannibalism in stallion genre novels, who in the end, was unable to escape from the whirlpool of destiny (not really).

- Description from Novelupdates