Superstar From Age 0 - Chapter 654:

In the age of mutants and technology, everyone is after power and eternal life, but Kiba lives for his dreams of lust and vanity.

A man on a mission to live the life to the fullest. The tale of the legendary Wife Hunter whose very name terrifies husbands around the globe.

This is the story of the devil who does as his heart pleases, unafraid of the labels of good and evil.

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

He rose from abjection and achieved eternity in glory.
He embraced the prettiest beauties and killed the strongest opponents.
He was able to shift the clouds into rain and cover the sky with one hand.
He could overrun the entire world and go anywhere as he pleased.
He pacified wars and held the world in awe.
He was matchless in the world.
However, his hair turned white overnight for his beloved woman and he was on the verge of death.
He was surrounded by enemies who were trying to take his life.
He struggled his way to become mighty and fought for everything he cherished.
For this age, he was the only king of the Dark World.
His name was a byword for might.
As a man living in the world, his only ideal was to pursue brilliance.

- Description from Novelupdates

“Breaking News! A 28-year-old IT worker beats three university kids to death with a spiked bat over a dog!”***Following the revenge, John took his own life in stubborn resistance, but that wasn't the end. He and his dog, Alfred, found new life after making a deal with an Eldritch God, Chuthulos.The duo reincarnates in another cosmos where Humans live an intricately connected life with Monsters as Tamers.However, in this perilous journey where his exposure to higher powers can lead to not only his death, but of the entire Eldritch Cosmos, John is not without help, for he receives the Rune of New Beginning, a power shaped into a system made from Eldritch Ancestor, to aid him.“So I can inspect all Monsters, eh? Awesome.”“Evolution Pathways? Cool!”“A private world where I can create biomes and habitats for monsters? A Monster Paradise?! Holy Land!”“Hey, what new function are you going to add in the next level up of the Rune, Chuthulos?”With all stacks on himself, John is determined to make the most of his new life with Alfred and his Pet Monster companions and keep his end of the bargain.