Netherworld Investigator - Chapter 280

The prospective college student Luo Ji, who is enjoying the last summer of the third year of high school, has undergone earth-shaking changes at this moment after accepting the invitation of the game friend and becoming the player of the game of “Civilization Rise”.
This is a war game between the world and the world, and it is a fierce collision between civilization and civilization!
To annex the five continents, sweeping across the three oceans, and see how Luo Ji led his people, in this powerful enemy look around, the battlefield of the heroes to fight for a battle to the most powerful imperial civilization!

- Description from uukanshu translation

I never thought I had meaning to my life, but I guess I have a talent too.

「Get ready. The duel will begin soon.」

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.

For Marco, Lucas is his meek little brother. For the rest of the world, he is the menacing Ghost of Vermil.“Angels endow blessings. Demons sow curses.” A hundred years ago, angels and demons descended on earth. It is said they are still here.Annointed with potent holy power, Marco is set to join the Kingdom's Holy Army to fight off the demonic legion. But before that, he must confront the trail of blood and ash that points to Lucas's involvement with the dark side.As mysteries unfold and loyalties fracture, Marco is faced with the question: where does holiness end and damnation begin? If all lines are blurred and the fate of humanity is at stake, will he have enough resolve to strike down the brother he once swore to protect?