Tokyo Ghoul: Madara Template Strikes Back! - Chapter 31 - 22

Welcome to Freia. A continent where evil magi ruled. Until firearms came, that is. Now the people live free of those demons…

More, however, must lurk beneath the surface.

Claude, a transmigrator from another world, finds himself in the midst of this changing world, attending ‘middle school’. Or, as he calls it, ‘boot camp’. His destiny was to graduate and join the military, but the future is seldom so simple.

His life, and the world, is set on the path of upheaval and chaos the day he finds a cookbook.

A magical cookbook.

- Description from novelupdates

In a world where martial artists reign supreme, strength is everything. Unfortunately, that logic doesn't apply to a certain Florida Man.

Refined in the nuclear fallout wasteland, Leo was the strongest mutant alive. He carried an alien artifact, allowing him to exchange his lifespan for modern items. After 50,000 years of solitary life in a humanless world, he collected enough lifespan to transmigrate to another habitable world.

Leo was later thrown into a mysterious planet. He soon discovered that his body produced radiation, and it mutated the surrounding plants and grasses. Worrying that he might ruin the beautiful planet, he chose to live in seclusion.

Unfortunately, the local population soon discovered his existence, and a misunderstanding ensued.

When Ye Mo suddenly woke up, he realized that everything around him seemed to have changed: He has been transmigrated into the modern Earth where spiritual energy is scarce. His pretty master from his former world was nowhere to be seen. Most importantly, he found himself in the body of a young man who has been abandoned by his clan for an embarrassing reason…

- Description from Novelupdates

This novel is also known as From The Start, I Traded A Galactic Warship

After getting a trading platform three thousand years later, everything in the world has become an antique, worth a thousand gold.

But it was also learned that three years later, aliens invaded, human beings fell, and the dark starry era began.

In this era of unprecedented change in tens of thousands of years.

Shen Shi decided.

First trade a space battleship, and then talk about it.

then–

Battleships come to the world from outer space! Global shock! Starry Sky Era, open in advance!

- Description from novelbuddy