Villain: Ultimate Mutation System in the Alternate World - Chapter 47: Silent Killing Part 2

This story is about a rookie researcher, who was forcefully dragged away from his restful life, compelled into facing various killers and zombies, always having to risk his life at the brink of death, and finally becoming an advanced researcher that is acclaimed by all. And throughout his adventure, he met an alluring(?) killing machine, who he started to have fantasies on after they had an accidental kiss…

Xiao Yan: Did I fall for him? But he’s a man!

Maya: Who knows…. maybe it’s the other way round?

- Description from Novelupdates

In the fantasy world ruled by Matriarchy, Kael of the Ancient Moonstone House, was working as a guild receptionist. Throughout his life, he was protected by his mother and later, younger sister, who was considered one of the highest potential individuals in the Queendom of Elyria. One day, he hears that his sister has gone missing and his family has accumulated debts of over 127 million gold coins to the Bank. The Queen comes to his rescue, paying off his debts and in exchange, he has to marry her five daughters, who each excel in a domain of their own.Having the five imperial princesses and the Queen herself as the backing, Kael has become one of the most protected individuals in the Queendom. Little did his wives know that Kael had another identity. He is the most dreaded yet noble Assassin of the imperial city, “K,” one who hunts down the criminals who escape punishment either because of insufficient evidence or using their connections.Follow Kael's journey, as he navigates his life as the protected figure in the light and protector of justice in the shadows.

Six years ago, he was the peerless God Ye, who had his entire memory wiped by a sinister plot. Six years later, his daughter was bullied and on the brink of death. With a single utterance of “God Ye,” the king returned! All his foes were utterly crushed! Starting as the War God, goddesses from all over the world sought him out...

Cayena, the Imperial Princess, was known as the most beautiful woman in the Empire. She was a woman who knew nothing but evil and luxury.

However, she was destined for ruin: she would be used as a chess piece by her younger brother to secure his throne and killed by her crazy husband.

“I’ll make you the Emperor.”

“… Sister, are you referring to me?”

“In exchange, give me freedom.”

She had to change things before she became that Cayena.