Machina Arcanis: Two Worlds Collided - Chapter 104. Broken. Lost. Forlorn.

“Save the world? Yeah, that's gonna be a no from me.”Noah had it all. He was one of the youngest billionaires in the world, tall, handsome, and usually had his pick of women.Life was perfect... until he was summoned into another world to defeat the Demon Lord.Unfortunately for Camelot, Noah couldn't care less about being their hero. All he just wants to do is go home. But the ritual home demands blood, power, and sacrifice. And if the world must burn so he can leave it, so be it.With the power of the abyss running through his veins, the dark dragon marches forward.“Your fate is bound to this world, hero. No matter what you do, you shall save this land.”“We'll see about that.”

In the middle of a deserted island, a small boy wakes up with two sets of memories: one from his few years of life and the other from a man who lived to adulthood and achieved great things. When he least expected it, a powerful master appeared on the island and took him in as a disciple, revealing a shocking fact: magic exists in that world, and, thanks to it, humanity managed to conquer the galaxy.

The world that nurtured the civilization which reached the pinnacle of magic was on the verge of destruction.
The last survivor transmigrated to the past, when the magic civilization started growing, as countless mages were still fumbling their ways through the thorny paths of magic knowledge.
He, who came from the end of the magic era, aim to reach the pinnacle of magic.

- Description from Novelupdates

Xu Jun finally defeated the BOSS–the Dark Demon King, in this stand-alone, virtual reality game. When he wanted to go out to browse Weibo and express his mood, he suddenly encountered a game BUG and immediately passes over to the game world.

He became the man who finally took down the Great Demon King in this world. Gratifying! The attention of millions of people!

……However, he did not know the development of this world was not the same as the game, the Demon King did not die, rather his soul entered into Xu Jun’s body; this Demon King knows of all the stupid things Xu Jun does everyday…….

- Description from Novelupdates