Online game: God-level Assassin, I Am the Shadow. - Chapter 124 - :The First Kill of the Emerald Level! The Soul Devourer Bloodline!

Gu Changge, a noble lady from a wealthy family, is a well-known business legend in Yuncheng, going into business at 15, taking over as President of Gu Group at 18 and becoming Chairman of the family business at 30.
She is murdered by her husband Shao Tianze, just to give his mistress Gu Changle a healthy heart. But a premeditated car accident makes Gu Changge revive in a new guise and settle into an 18-year-old girl, Song Yunxuan.
The new face, young body and experienced soul become her weapons of revenge. In her struggle with the four big families in Yuncheng, can Gu Changge shrink back? Will she open her broken heart again? Can she always head off dangers in power struggles?
Let’s find out if Gu Changge can revenge herself and create glory again.

- Description from Novelupdates

Lucien, a guy who has nothing but the desire to save his mother. To get strong enough, he makes a contract with the demon of L.u.s.t. And now, only by making a great harem, will he gain the power to protect those dear to him.

I became a side-character who died in anguish because of her good-for-nothing husband.

If I can’t avoid getting married, why don’t I change who I marry instead?

“Excellent, marriage sounds good.”

“Wise choice. Then let’s have a wedding ceremony that isn’t too ceremonious. Following that, I’ll need you to go down to the Fief and behave like the lady of the house until I call for you. Naturally, there won’t be any time to spend in leisure whilst dousing yourself in luxuries.”

“I’m not marrying you, but your father instead.”

“……Pardon?”

“I’m not going to marry you. Do you have a problem with that?”

"In her previous life, she is used by her first love to send her own company into the tiger's den. She becomes bankrupt, gets kicked out of the house by her father, and becomes the target of ridicule by the family. Worst of all, she believes her best friend's lies, thinking that everything was done by her ‘husband’. Under her best friend's ploys, she almost kills him and is ultimately sentenced to prison, where she dies of depression.