Magika no Kenshi to Shoukan Maou - 4.1.3 — To the End of the Peaceful Day

Urano, a bookworm who had finally found a job as a librarian at a university, was sadly killed shortly after graduating from college. She was reborn as the daughter of a soldier in a world where the literacy rate is low and books were scarce. No matter how much she wanted to read, there were no books around. What is a bookworm to do without any books? Make them, of course. Her goal is to become a librarian! So that she may once again live surrounded by books, she must start by making them herself.

The mysterious boy Ling Chen is saved by a little girl as he lay on the street dying. Years later, he strikes a deal to save this savior-turned sister and enters the virtual world. In a future Earth where advanced warfare has forced nations to settle issues virtually or else suffer the consequences, Ling Chen bursts into the scene and goes from unknown to legend. Yet all is not as it seems, for Ling Chen has a dark past, and there is a greater mystery at hand behind this virtual world.

To save his terminally ill little sister, Ling Chen enters the newly released virtual game world and joins a small gaming studio comprising entirely of women. From now on walking upon his path towards the pinnacle. An ancient, evil item almost forgotten by history, the “Lunar Scourge” helps forge his unsurpassable legend, and causes him to unknowingly step upon a path that is destined to be punished by the heavens, the way of the Shura.

- Description from Novelupdates

Transcend to become the prince of Daxia, activate the Devil Emperor Summoning System, summon the powerhouses from other worlds, and fight for hegemony in the heavens!

If I were the Devil Emperor in the future, I would definitely let your blood stain the sky!

- Description from novelbuddy