As the Minor Gay Love Rival in Het Novels - Chapter 9.7

He Lang died by his own hands for the sake of his imperial younger brother’s ambition, whom he loved. He was offered to be reborn in exchange for giving up his past romantic feelings. Reborn without the burden of his romantic feelings, he brings with him a manual to new worlds. He wholeheartedly followed the instructions of the manual to complete the tasks, not knowing that the originally slag gong was blackening…
He pleaded to his affectionate Emperor brother to release him, he pleaded to the paranoid prisoner next door, but until the end he remained baffled.
In the end, he discovered that the full name of the manual was – “Slag Shou Cultivating Manual”
Σ (っ ° ° °;) っ!

- Description from Novelupdates

Lin Yu finds himself transported to the world of Honkai: Star Rail.Equipped with a divine mobile game development system, his first project is creating “Honkai: Star Rail.”Soon, his game captures the attention of the entire universe.As players reach the Cocolia boss battle, the song ‘Wildfire’ begins playing.“Woah?! This is a turn-based game; how dare you make it so intense!”“The moment this music kicked in, I felt like I was about to take down an Aeon!”Progressing further, they encounter Dan Heng’s sea-parting scene.“I thought ‘Wildfire’ was intense enough, but there’s even more fire here!”“Dan Heng, still denying you’re Imbibitor Lunae? Now you’re a five-star limited character!”Arriving at Penacony:“Huh? Have you listened to ‘WHITE NIGHT’?”“Acheron’s power has been tested – fellow gamers, feel free to pull for her!”“Duke Inferno: Children, this isn’t funny.”“Before experiencing the story: Aventu**ne? Just another profit-driven fraud! After the storyline: May the Mother Goddess thrice close her eyes upon thee…”“What Aventu**ne?! He’s clearly my unfortunate yet loyal bro!”

I found myself possessing the body of a young master who everyone was eager to kill. I’m invincible, so let them try to kill me. It’s only for one second, though.

In the 21st century Earth gave Birth to greatest genius ever. A genius who Master myriad of arts. Medicine to Engineering. Mathematics to Micro Biology. Weapon Designing to Environmental control. Music to Painting. Dance to Martial arts. He mastered Everything.