I am, Flame-Chaser of Previous Era - Chapter 17: Mobius?!

The protracted ’witch hunting’ had faded into silence with the end of the Seven Years’ War, and the mysteries of the East Coast had begun to conceal themselves, yet gunpowder was on a rapid rise. Mo Qishang, who should have been utterly confounded, stood at the crossroads of destiny in the name of Arthur. He stared in astonishment at the charging knights, the wizards atop the high towers, and the bizarre wilderness. He felt the sharpness of the longsword and the recoil of the firearm, both clear and unfamiliar. At last, he excitedly shook his robe and, with a smile on his face, said— “Do not believe what I say, for to believe is to exist!”

Three Days of Happiness is a novel by Sugaru Miaki, also known as Fafoo. It’s a rewritten version of the story originally posted to 2ch.

The premise of the story revolves around a shop where one can sell away the remaining years of their life, and the consequences of doing so.

“I Say A Little Prayer” is a short related story which was posted along with the novel’s release. It spoils some things about the main story, but nothing major.

Kai’s life was small—coffee-stained mornings, cracked recipes, and a system in his head that tweaked toasters and dough like it was nothing. Then the sky shattered. Aliens—Skraiths, jagged and brutal—invaded, tearing his city apart with green-glowing weapons and relentless claws. Superhumans rose to fight back, fire and lightning blazing through the chaos, but Kai’s world crumbled with them.Hiding in his apartment, Kai stumbles on blood—human and alien, smeared on his wall after a superhuman battle. His system, once just a tinker’s tool, awakens, offering him a choice: mimic their powers, temporary and wild, through the blood itself. Desperate, he takes it—stealing pyrokinesis, then electrokinesis, then kinetic energy, each power burning through him, fading fast. But it’s not enough. Armed with a humming Skraith weapon and a body tougher from alien blood, Kai joins a ragtag crew of enhanced fighters—Liv, Rylan, Jace, and Tucker—scraping to survive in a warzone where every shadow hides death.As Skraiths swarm and the city burns, Kai’s system pushes him deeper, analyzing, integrating, crafting minor enhancements—durability, strength, sparks of power that could make him a target or a savior. Government factions, rogue scientists, and the aliens themselves start sniffing around, drawn to his strange tech and blood-stolen abilities. By the time Kai crafts his first super-powered enhancement—an artificial strength boost—he’s no longer just a tinkerer. He’s on the edge of something bigger, something dangerous, where blood and sparks could forge a hero—or break him entirely.In a world unraveling, Kai’s fight for survival becomes a desperate race to master his system, outrun the Skraiths, and confront the truth: the power he’s chasing might destroy him—or remake the world.

This is a century glittering with the brilliance of human civilization, a world where steam engines, magic, and demi-humans coexist, a chapter of complaints committed due to exploration.'Red Dragon Queen rises first, annihilating all human affairs with her wrathful flames.''The mysterious child of the sea will raise great waves to erase the sins of humanity.''The god of the skies will leave no refuge for the remnants, nowhere to belong.''The immortal witch composes epitaphs for them with her magic.''And I, will write a new chapter for this world'... ...... ...Years later, Fisher, who has received the apocalyptic prophecy and the miraculous tool called the Demi-Human Girls' Completion Manual, wishes to be recognized as a pioneer in demi-human academia, a savior of human civilization, a dove of peace, and a messiah.Instead of being the person who is torn apart with the firewood knife, and the savior divided into pieces.