Instant Death - Interlude - The fact you are seeing this reflection (End of the 1st Volume)

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

With the Goddess’ blessing, he became a 『Divine Knight』 and founded an Empire.
As time passed, he grows older, and by the time the heavens called for him to come, the Goddess showed before him, asking for his last wish.

He wished to be reincarnated in the future.
He dedicated all his life for his people, he had no time to master his own arts.
This time, he wishes to live for himself, forging his body to the utmost limit.

The Goddess complied with his wish.
In the far future, the King shall reincarnate as the 『daughter』 of a renowned Knight family.
And, under some circumstances, she is labeled as a failure of a Knight, however——

「How convenient. I can stand on the foremost line without needing any rank. No better training than actual combat!」

Thus, the legend of the world’s strongest, most beautiful Knight Disciple (♀) has begun—

Upon opening his eyes, Muyang realized that he found himself in Dragon Ball’s world filled with dangerous people like Vegeta, Frieza, Cell, Majin Buu.

Once all people received Souls and incredible powers. Some were lucky enough to obtain the Soul of an ancient and powerful creature, but fate was not favorable to all.

The world began to change, and creatures evolved. But, it was not the beginning of a new era. It was the end. A couple of months later, a dark mist appeared and destroyed the world. It was a dictate of destiny from which no one could escape.

Wain Norheim was the world's best assassin and the only one who didn't get a soul. However, he was destined to gain the power to confront fate.

Escaping through a portal into another world, he unknowingly began the apocalypse. Even the world failed to expel him.