MTL - The Devil’s Cage - Chapter 28 Bleeding night

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

Live again, earn money well, and live life slowly. General group: 841193493

- Description from novelbuddy

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

This book features a slice-of-life style with minimal system presence, welcome to enjoy.[Theoretically, this system can target any cognitive being in the universe.][After selecting a target, the host will randomly acquire the target's skill level and talent.][When the target is of the same gender, skill experience acquisition speed +50%, skill level cap -50%.][When the target is of a different species, trigger 404 aura, skill experience acquisition speed +100%, instant death probability +99%.][After a failed targeting, the punishment mechanism is activated, halving the host's basic stats, entering an absolute weak state, and resetting skill levels.]Traversing into this world, Bai Chuan Ze Ping observes this problematic system, then looks at the top student and beautiful girl of the class...Hmm, perhaps... this classmate could be a fine learning companion.PS: This book is also known as “My Talent Comes from My Girlfriend.”