MTL - Science and Technology Library - Chapter 7 :virus?

Time travelling from the majestic era after the Recuperation of Reiki, he became Kimura Kazuki, a 16-year-old high school student in Japan, one year before the Reiki Recuperation.

Tentatively, he set out to hone himself to the bone, burning candles at both ends to stockpile resources in preparation for the imminent Recuperation of Reiki. His goal was to be many steps ahead of all humanity when the time comes.

However, it seemed like fate had decided to play a cruel trick on him.

One year later, the Recuperation of Reiki… did not happen as expected.

- Description from Novelupdates

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.

The traitor Gu Mang returned to his home kingdom again. Everyone rejoiced in his banishment. It was said the one who hated him most was his closest friend – the cold and stoic Young Master Mo.

A rumour: Young Master Mo prepared three hundred and sixty-five methods of torture to try on Gu Mang, enough to play with him for a year without repetition.

But what’s the truth then?

Well the truth is even more unspeakable–

Mo Xi’s identity: the most abstinent commander of the empire.

His relationship with the traitor Gu Mang: they’d slept together before.

- Description from Novelupdates

What should I do if I cross to another world and become an NPC?

This idea has been deeply rooted and sprouted in William’s mind!

Therefore, he decided:

I want to be the strongest NPC in history.

Wear the thickest armour and give the most vicious beatings!

Who says an NPC will be killed by players?

Who says an NPC upgrades more slowly than players?

Who says an NPC must explode equipment, I can explode in more ways… Bah humph.

Anyway, it’s impossible for me to die. Just take a look at all you trash players. Your father will stand here and let you chop for an hour without a frown!

- Description from Novelupdates