Returner Fantasy - Chapter 14: Returner Fantasy - Guilt (R18)

Reincarnated into the muddy guts of a cursed swamp as a tsetse fly, former office worker and master-level cynic Buzz Windbreaker quickly discovers that survival is both absurd and magnificent. The air is thick with poison, the predators are many-limbed and spell-woven, and the prey? Just as desperate as he is.Yet with every drop of blood he drains from beast, beastkin, or unlucky mortal, Buzz unlocks fragments of an ancient arcane lattice that spirals beneath the skin of the world itself—a system of runes, incantation spirals, and primordial energy flows forgotten by even the highborn mages.His evolution isn't just physical: it is architectural. Each new form is built like a spell—symmetrical, efficient, cruel. Wings shimmer with sigil arrays. Proboscises become siphons of mana and memory. Legs are sharpened to runic blades. Jokes sting. Death stings harder.Soon, Buzz isn't just hunting. He is ascending.

His name was Brayden Neal, and he was an ordinary citizen. At eighteen years old, he was bestowed the title of a king!

After ten years of fighting in the northern borders outside the kingdom, he finally returned home. He swore to kill three people the moment he arrived at the capital…

When an era came to an end, various forces set foot in cultivation to compete for immortality. A young boy who spent most of the time sleeping got lucky in the troubled times and became an unparalleled immortal who could cover the sky with a snap of fingers. Was he going to live forever?

- Description from Novelupdates

He wants indoor plumbing. They think he’s conquering the world.Arthur was a genius engineer on Earth, capable of optimizing global logistics and automating entire factories. But he lacked one thing: common sense. Now, reincarnated as Arthur von Pendelton, the six-year-old son of a powerful Duke in a medieval fantasy world, he faces his greatest challenge yet: Drafts.Armed with the T.E.C.H. Interface (Trans-Epochal Construction Heuristic), Arthur can analyze magic like code and build modern technology from scratch. His goals are simple: Double-glazed windows, hot showers, and a toaster that doesn't burn the bread.But there is a problem. The people of this world don't understand engineering.He builds a high-pressure boiler for a bath; his father thinks it’s a “Dragon-Breath Siege Weapon.”He creates a hydroponic garden; the local church declares him the God of Harvest.He ignores a Princess's flirting to analyze the thread count of her dress; she thinks he is playing “hard to get.”Follow Arthur as he accidentally industrializes a kingdom, terrifies his enemies with home appliances, and remains completely oblivious to the fact that he is becoming the most powerful man in history.All he wanted was a warm bath.