Hang-up One Second to Achieve Lv.999 - Chapter 40

Mechanics fix things.Fighters break ‘em.Those were the two truths Perry lived back on Earth. When he got isekai’d into a young noble with newfound magical powers, he found himself stuck with an awful choice. Try to survive on the Front, the mystical battleground where Hydras and Devils roamed free… Or find another way.So he took an oath. An oath that made him a Magus Dominus. A mage lord. He’d escaped his fate, least for the moment.For most his life, Perry was used to being alone. When he got sucked into Ro'an, he was suddenly thrust into the role of surrogate son to his loyal servant and half-brother to a tempestuous Storm mage. With their help, Perry prepared his best to be lord and protector for his domain. And if he fought a few monsters, and helped a few people along the way, well…Mechanics fix things. And fighters break ‘em.-Progression Fantasy with light LitRPG elements-No romance-Kingdom building and magic progression

The scum’s or villain’s long road of transformation was tentatively set to the world:
The abandonment of the educated youth’s wife (Completed)
The hidden marriage of the scum film emperor (Completed)
The best brother in the world (Completed)
The Phoenix male who destroy the bridge after crossing the river (Completed)
The treasonous general (Completed)
I’m an honest man (Completed)
To become the top scorer in the School of Agriculture (Completed)
The soft rice man’s self-cultivation (Completed)
The whole world is reborn (Completed)
I want to survive on a desert island (Completed)
The stallion male who has seized the opportunity (Completed)
The perverted self-salvation (Completed)
The spring of the loafer (Completed)
The misplaced life (Completed)
The miser career (Completed)
The ghost is out of feeling (Completed)
The Queen’s favorite husband (Completed)
The vicious girl with her godfather (Completed)
I want to be a good person (Completed)
I does not tear up the family (Completed)
The perverted common plant (Completed)
The Mary Sue’s men (Completed)
Every time I was reborn, someone wants to kill me (Completed)
The old people’s counterattack path (Completed)
The global evolution (Completed)
When I became a net red (Completed)
For you, good person (Completed)
His heart had white moonlight (Completed)

- 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.

After the nuclear warfare, massacres started to spread throughout the entire world. The order between humans completely collapses, and the strong eats while the weak gets eaten becomes the #1 rule.