Devil's Son-in-Law - Chapter 1056: Wisdom

Qin Lin was electrocuted by playing a nostalgic “Ranch Story” game, and suddenly gained the ability to enter the game. He also found that he could bring the watermelons grown in the game out of reality.

At first, he calculated that a pound of watermelon would sell for 2 yuan. As long as he sells 10,000 catties of watermelon seeds in the game, he can earn 20,000 yuan a day.

Later, he discovered that by upgrading pastures, he could obtain advanced crops beyond the world, raising livestock to obtain advanced livestock breeds that were far beyond the world, and building factories to obtain various formulas that were far beyond the world, and everything was different.

- Description from novelbuddy

The world was once at war with 10 alternate worlds. This was known as the Concept War and our world won 60 years ago. All of this was concealed so no normal people are aware of this fact in the current time.

After the death of his grandfather, the high-school student Sayama Mikoto is suddenly summoned by the giant corporation IAI. He learns this world is headed for destruction due to the acceleration of the Minus Concepts. To prevent this, negotiations must be undertaken with the survivors of the other parallel worlds so their 10 concepts can be released.

And so Sayama is caught up in the final battle to clean up after the Concept War which left behind so much enmity.