The Bookkeeper - Chapter 19: Silence Domain

In an alternate world, a demon disrupts dynasties, harvests souls, and refines a banner of ten thousand souls.Under the heavenly tribulation, his body and soul are destroyed, but the Ten Thousand Souls Banner protects his undying spirit. Unable to possess a body, he's countered instead.A laid-back young man in society, wielding the Ten Thousand Souls Banner, roams the human world.With the Ten Thousand Souls Banner in hand, I refine a Golden Core with good deeds.A slice-of-life story with no ambition for conquest, helping the departed fulfill their wishes, gaining merit to repair the Ten Thousand Souls Banner, and enjoying a laid-back life.

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

Just like how everyone adored heroes in their childhood, a certain young man adored those powers hidden in shadows. After hiding his strength and living the mediocre life of a mob character by day while undergoing frenzied training by night, he finally reincarnates into a different world and gains ultimate power. The young man who is only playing at being a power in the shadows, his misunderstanding subordinates, and a giant organization in the shadows that gets trampled…. This is the story of a young boy who had adored powers in shadows possibly eventually reigning over the world of shadows in another world.

mc gets transmigrated to Fallout New Vegas with the merchant system. let the questionable adventure begin.