One Piece: A Warlord's Path - Chapter 587: The Paramount War: Enter the Stage

Yang Yi crossed over the world with a storage space with him. He ended up in some desolate wilderness populated by flying beasts and dangerous predators and also crawling poisonous bugs and snakes. To prevent getting bitten in the ass by venomous bugs when going to the toilet, let the great infrastructure begins –
Our goals are:
Eat well till full stomach.
Having clothes to wear but also being good looking.
To have a house that could cover all seasons.
Roads that leads to every place; develop agriculture, industry and commerce together.
No shortage of both material and spiritual needs.
He was DETERMINED to build a safe, comfortable and prosperous modern city in the wild world together with the native tribe with max efforts.

- Description from Novelupdates

The male student, Fukai Nagamasa, ignores his studies for college entrance exams in favor of following the path to chuunibyou. As he fainted during night cramming session before the exams, he realized that he was transported to a parallel world as a feudal lord in the Sengoku Era. Not to mention that suddenly, he was marrying the sixth Demon King, Oda Nobunaga’s little sister, the one who was purported to be an unrivaled beauty?

The dark BOSS, who had the fortune of becoming Earth’s last living human, brought with him his loyal, second last human to die, little brother to be reborn.

The best way to declare war on a spy as an ordinary person is to become a spy as well.As a spy, if you want to go to war with a powerful espionage organization, join an equally powerful espionage organization.If you are unable to join any powerful espionage organization, then establish your own espionage organization and fight until destruction or victory.This is the war of spies, telling the story of how a group of ordinary people achieved extraordinary success.