Ryuu Kusari no Ori -Kokoro no Uchi no “Kokoro”- - Chapter 3[LN] Volume : .3

This is a story about the protagonist getting the system, going crazy in the biochemical apocalypse, producing aircraft and tanks, destroying zombies, saving good people and killing bad people.

- Description from novelbuddy

A calculating merchant of noble birth lives a comfortable life managing his guild's business at the Imperial Academy—until lightning strikes him, leaving him with prophetic visions of a disastrous future. In these visions, he's expelled from his family, branded a traitor who aids demons, and worst of all, becomes a penniless beggar. When the supposed “protagonist” of these prophecies enrolls at the academy, he realizes his countdown to ruin has begun. Now he must use his foresight to rewrite a story where he's cast as a third-rate villain, all while navigating ancient dungeons, demonic threats, and the troublesome “hero” who might be the key to changing his fate.#MoneyIsEverything

Fade was a legendary assassin that could kill just about anyone, as long as the price was right and the reason was just.

One day as he was reminiscing about his life when he lost someone important, he fell asleep. When he woke up he was in a weird place, a different body, a different world.