Ryuu Kusari no Ori -Kokoro no Uchi no “Kokoro”- - Chapter 7[LN] Volume 1:

However, he did not know that he was not raising just a harmless pet, but a biological weapon secretly made by the government… a real monster.

As a former librarian, Rand felt that he had been living an ordinary life, the one that he had reclaimed unconsciously every single day.

Recently, he has been a little upset because the pet fish he accidently brought home to raised seems to have undergo some strange changes

Well, it turned into a merman.

- Description from Novelupdates

I exist in the darkness, disappear under the bright light, and will eventually devour the sun and turn into the shadow of all things… Known by people as the indescribable terror of darkness; the king of shadows; the dark day; the existence of the shadow of the world , is still just a somewhat special high school student, facing a weird death game…

- Description from novelbuddy

This novel is also known as Farming And Learning Martial Arts To Bring Peace

The world is difficult and dangerous. Chi Qiaosong’s family has only three acres of thin fields, but he allowed him to grow a splendid world.

…

Two? Two new stories, Bai Yuhan worked hard to conceive, please watch.

- Description from novelbuddy