MTL - Metropolitan System - Chapter 16 Is this about?

Humanity was living peacefully on Earth for millions and millions of years until the day unknown monsters from beyond space invaded them.

When humans were about to disappear, some people with abilities came out to the light and shared their knowledge and powers with the world, and together, they managed to push back the invaders during a terrible war that had lasted for years.

This war had created many orphans, and among them, Kye had lost everything, even his parents. And the only thing he received from their death was a pale-looking necklace.

However, once the necklace finally activated, a system was given to him, and his life changed completely.

The system gave him quests to do, and Kye complied. He was getting stronger every time he achieved them, until the day it gave him a weird quest.

[You have one day to kill the one who had sinned. If you do not kill, you will die.]

“Verily, after sorrow shall come great joy.And after this pitiless winter shall come a gentle spring.Be patient my child, you only need wait to receive its soft rains.”There wasn't much good that could be said about Leon or his life in general.He'd been raised by his single mother in the bad parts of town, Neither he nor his sister knew their fathers, He'd dropped out of school early on to make ends meet, something he'd barely done even with him and his mom working their asses off.To top it all off, the useless son of a gun that was apparently his father had genes that were susceptible to cancer. So at the ripe age of 18, he was diagnosed with terminal cancer.Such suffering would've almost been comical, if it wasn't his life.Having lost his physical ability, he finds work writing novels online to help with the bills.And then the world took his family from him.Left in a hospital with terminal cancer, american healthcare and his novel as his only companions, Leon decides to end it all.Only to wake up as Victor, an extra in the brutal world of his novel. His troubles were only just starting.Soft rains be damned.

He was the cold-blooded prince of the Jin country. Decisive and smart, he had looked down on the world with apathy and disdain.

All the people came to the Chaos Continent, became the lord of one party, and participated in the struggle for hegemony among all ethnic groups.

Tinder is the authority of the human lord. You can sign in on Tinder every day to get population, blueprints, food and other materials.

Huang Yu signed in on the first day and got a discounted artifact.

A batch of discounted products will be refreshed every day for Huang Yu to buy.

then……

“This legendary weapon is only 10,000 magic crystals after the discount? I bought it!”

“0.5% off dragon eggs? Give me 100!”

“0.0…01% off the extraordinary arms training camp! There is such a good thing? Come to the bowl!”

…

Since then, Huang Yu and his territory have become famous in the Chaos Continent!

- Description from novelbuddy