Online Game: I Possess a Monster Merging Simulator! - Chapter 322: Merging Demoness!

A failed investor from 2017 got drunk and woke up in the 1980s. China is just opening up, and the economy is blooming. There is also the dissolution of the Soviet Union, the bursting of the Dot-com bubble and other financial crisis. He used his knowledge of the future and slowly build up his empire.

- Description from novelupdates

Perhaps it is the choice of fate. As a senior otaku, Qian Lingfeng got the “steel shell system”. However, when he swept the world with the system, became a local rich man, made all kinds of beautiful women, opened a harem, and realized the ultimate fantasy of thousands of otaku, he found that things seemed far from simple!
When the end comes, biochemical zombies suddenly come down, fierce beasts are in power, bloodthirsty zerg roam to kill the world, and human lives are comparable to dirt. Where will weak human beings go in this world? Is humanity going to be extinct? Or … can an otaku save the fate of the human race?

- Description from Novelupdates

When Lin Su discovered he could travel between two different worlds with his tamed beasts, the world gained a Beast Tamer formidable in a way that defied science.-----------------------------------Without a system, without a female lead, Crossing Two Realms, original taming beasts

The world changed the day that cracks appeared in the sky– suddenly monsters named『Demonic Beasts』appeared and began to rampage, attacking people.

Meanwhile, girls called『Magical Girls』began to appear to counter the demonic beasts. As they defeated the demonic beasts, gradually people’s lives gained a semblance of composure.

–but when there is light, there is also darkness.

In the corner of an alleyway, a boy who had been attacked by a demonic beast was dying. His voice begging for help did not reach anyone and his body refused to move.

「Boy. Do you want to be saved?」

Looking into the boy’s face, a black cat began to speak to him.

The boy nodded firmly to the devilishly sweet invitation, in response the black cat mocked him.

「Is that so—then I’ll【Haunt (Save)】you」

—on that day, a『Magical Girl』was born in a place that no-one knew.

『She』never laments, no matter what the future may bring.