Kaijin Fighter: So I Have to Make Monsters, So What? - Chapter 6: Sometimes Playing Hero Gets you Shot at

This is the story of a crazy lich who possesses an internal game system and brings catastrophe to the entire world.

On the will left behind by the 14 year old suicide victim K:

“Taku Sugawara is the devil. Nobody should believe his words.”

She is the underworld Ghost Doctor’s only disciple, who accidentally transmigrated into the body of the main wife’s daughter in the general’s mansion. She used to be a punching bag.Now, she stepped on her dregs of an older sister, put her father’s concubine in her place, and teaches any objectionable aristocratic ladies a lesson.

Her days are rather free and unfettered. But when did that cold as ice prince from the rumors, sporting a deadpan face all day long, fix his gaze on her?
He unexpectedly fawned and pandered to her like a devoted dog?

“Go away, you rotten man! Careful or I’ll needle you like a pin cushion!”

“Wife, why are you so fierce? As a husband, I’m so scared”
….the man is all smiles as he approached, his eyes gleaming with a cunning light.

- Description from Novelupdates

Due to investigating an arms case, he was forced to become a gigolo, from then on, the cute little loli, the sweet and pure young married woman, the cold and aloof CEO beauty, and all kinds of other beauties surrounded him.