I am a Gao Fushuai Villain - Chapter 518:

Utsuro no Hako to Zero no Maria, or The Empty Box and The Zeroth Maria, tells the sinister story of Kazuki Hoshino, who is almost madly attached to his everyday life, and his antagonist Aya Otonashi, who suddenly transfers into his class—for the 13,118th time. She majestically announces to “break” him, without paying heed to anyone else around them.

Lin Yuan, carrying the “Door to Myriad Worlds,” transmigrated into the Great Universe of the Starry Sea.Here, the mightiest could obliterate star systems with the flick of a finger, and traverse millions of light-years in an instant.As a bottom-dweller, Lin Yuan could only rely on the “Door to Myriad Worlds” and his innate talent, “Against-Heaven’s Understanding,” to travel through countless worlds, silently growing stronger.【Your Against-Heaven’s Understanding allows you to cultivate the Muscle-Tenden Transformation Bible, comprehending the ‘Muscle-Tendon Transformation Blood Tempering Divine Technique’】【Your understanding is Heaven-Against, upon extending your comprehension to the Thunder in the Palm, results in the mastery of the ‘Thunder Creation Opening Technique’】【Your understanding is Heaven-Against, while observing the birth and death of worlds, leads to the insight of the ‘World in the Palm’】【Your understanding is Heaven-Against,, through studying the art of external incarnations, culminates in the ‘Self-Transformation Great Technique’】……In his unending travels, Lin Yuan ceaselessly grew stronger, until… he was unrivaled across all worlds.

The protagonist transmigrates into a novel and gains a system where they grow stronger by simply writing in a diary.July 7th, sunny: “The boss’s outfit is hideous again. Wouldn’t it be better to wear something cooler?”July 7th, evening: “I’m about to have my engagement called off. So excited! How should I act?”July 7th, evening: “Lin Qingyue, the female lead, is probably going to drown her sorrows in alcohol.”The protagonist thought it would be easy—just jot down daily musings, record life’s events, and earn rewards. All while playing the part of a villainous, bootlicking second-generation rich kid, moving along with the original plot.But unexpectedly, the female leads gain access to copies of the diary entries.One by one, they stop following the script, and the plot spirals completely out of control.July 10th: “The female boss is an idiot—no one would want her.”Soon after, the protagonist gets punished at work, all because they entered the office with their left foot first.

The unparalleled Demon King Ye Xuan, who was able to heal the death or the living alike and holder of the medicine Holy Scripture, was betrayed and killed by his fellow Demon Kings. But he reincarnated into the body of Ye Xuan, the prodigal son of the Ye family and vowed to himself that he would return to his peak and take back everything that belonged to him!

- Description from Novelupdates