My Ex-Girlfriend is the Strongest Guild Master and I'm the Weakest! - Chapter 4: Emergency Maintenance

Luo Zheng is at the bottom of the Luo Clan hierarchy, despite his family being the founders of a power refining technique that could instantly defeat any opponent.

One night, enraged by unfair treatment from a family steward, Luo Zheng burns the family records. In doing so, the hidden magic in the book engulfs him and Luo Zheng becomes a new skilled fighter. Fleeing his home and despicable clan, Luo Zheng must learn to harness his powers to rescue his younger sister while his own cousins are on his pursuit.

- Description from Novelupdates

A human from Earth is thrust into the [Hunter x Hunter] world, becoming the Zoldyck family’s defiant, red-eyed prodigy. They call me a genius and the rightful heir, but I say that’s Killua’s burden to bear.Armed with crimson eyes, and a subtle yet powerful system, I’ll rewrite destiny, upend the world, and embrace the chaos with a wicked grin.

“A Virtual Dream Device? What the heck is this?”“Is it used for daydreaming? Nope, not interested.”“What? It could simulate reality at a hundred percent? I could live out half a year in one night's time and bring in a replicate of a real person?Hmm, pretty sweet I must say.”“I'll be the only one left in the world while the others are all gone in the first dream?”“Uhm, I'll like to bring in a female celeb at the pinnacle of her glamor, could I?”

Two thousand years ago, the Emperor slayed a dragon in the wild, inaugurating the era of mankind.Since then, whenever malevolent dragons wreaked havoc, heroes have always emerged as destined, allowing time to flow across a long and peaceful human world.As the century turned, the sudden appearance of individuals with supernatural abilities triggered unprecedented disturbances. People constructed a sanctuary for these superhumans in the sky, on the back of a colossal dragon, called the Dome City.One spring day, Gongsun Ce, who had just started university six months ago, encountered a hunter who claimed to be a Wuchang master.“Hey, can you really do such a thing?!”“It's quite normal, because I am a superhuman.”—Thus, the love-comedy battle of supernatural abilities in a youthful campus begins!