The Genius System Without Equal - Chapter 4: The Ex and the Current

One night she gets drunk and mistakes the most well-known Mafia boss for a host and intends to sleep with him.

Oh my! What should I do? It’s best to run away!

- Description from Novelupdates

Seven billion humans living on the Earth time-traveled together after they had woken up one morning. They all heard a synthesized female voice.

When a terminally ill young man awakens in the world of his favorite childhood game, he realizes he isn’t the protagonist, the destined hero, or even a major side character. Instead, he has become an extra—a disowned noble barely clinging to relevance in a world where strength determines everything. Worse, his fate in the game was to die an early, meaningless death.Armed with only his knowledge of the game’s storyline and a common system that tracks his stats and skills, he is determined to survive. But mere survival isn’t enough. He remembers a hidden easter egg from a long-forgotten anime collaboration: the Mangekyō Sharingan—a power limited by game mechanics but unrestricted in reality.With Kamui as his trump card, he walks the fine line between fate and freedom, seizing power from the shadows while avoiding suspicion. As the protagonist and his allies battle against demons and unravel the game’s grand destiny, he secretly builds his own strength—manipulating events, mastering forgotten arts, and even forging ties with villainous factions.Will he remain a footnote in history, or will he carve his own legend in a world that was never meant to be his?

The world is terrorized by the powerful Black Witch who has been sealed in the moon. Every ten years, the night of Hexennacht arrives and a chosen witch must battle the Black Witch in hopes of finally defeating her.

As the current decade’s Hexennacht approaches, a mysterious girl named Kagami Kagami arrives and meets Horinouchi Mitsuru, the daughter of the previous Hexennacht representative.

It takes place between Kyoukai Senjou no Horizon and the City Series, two other series by the author.