Reborn with an Old Enemy on the Day of our Marriage - Chapter 103 - Extra 8: That Weibo ID Affair

Before going to college, an ordinary high school student went to celebrate and got drunk. When he woke up, he found himself in a completely different world. There was a big sect, the approaching sect entrance examination, a slum where his body’s previous owner lived, and a shared memory about a missing young girl.

When he got tangled in a fight with a few punks in this different world, he fell off a cliff and miraculously found himself still alive, with two more voices ringing inside his head. They were Sword Master and Saber Master. In the company of them, he continued to find out more about this whole new world. He took the sect entrance examination, entered the sect, met a strange man in black, and even participated in a major competition of the sect to have a chance to win over his peers!
In this whole new world, he was born again and got to explore the fantastic martial world!

- Description from Novelupdates

The story is about a man who’s opposed to the now-common practice of implanting false memories, but is one day given memories of a fictional childhood friend. This fabricated happiness torments him, but then, to his surprise, he meets her – a girl who shouldn’t exist.

On that fateful day, a voice in the sky told everyone on Earth that the world they called home has just been part of some sort of simulation.

In a future city intertwined with science, magic, and various races, a fearsome villain lives.“How dare you try to use such a young child. Do you have no conscience?”“It’s truly regrettable. To think that this girl could be the key to eradicating a den of evil.”“You can rest easy now. We will definitely protect you.”Sorry, but I’m actually that villain…It seems like a serious misunderstanding.