Leviathan of the Covenant - Volume 4, Chapter 3 - Sea, Swimsuits and the Mysterious Stone Fragment

Once upon a time, a hero had been summoned to a different world in order to defeat the demon king. After the war stretching 3 years ended the commendable hero slew the demon king. And he was forcibly deported back to earth after being dismissed.

Such bullshit!

Elves in addition to beast race, dwarfs and demon race. Even though I wanted to make a harem in the different world I saved! My dream will not come true on earth, where there is no magic at all. Thus, the hero returns on his own. Without the blunder of being extradited to earth this time, he will build a harem of his own in a different world.

[*Ding*

Evolution, it is the process with which the most fit for survival pass down their winning traits. What if this could be done on one animal, one object, one person, what traits would evolve.

...

Humanity has been entered into the grand inter-realm competition for sovereignty of all realms.

Darwin has been granted the gift of evolution

“There are always people who want to be evil!”

“The end of the world is coming soon, I must survive!”

Shen Cong, a patient of paranoia, saw other people’s opinions on the Internet about the end of the world in 2022, and immediately believed.

After which, He didn’t go out of his home, stayed and built his own doomsday vehicle, honed his ability to survive. Until one day, Doomsday actually came.

- Description from Novelupdates