Tensei Shite Inaka de Slowlife wo Okuritai - Chapter 167: The Exchange of Offense and Defense Between Mother and Son

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

Stella Wilson, a nice rural lady who went to New York to pursue her Veterinary degree. Also, she works part-time as a pet sitter to a three little cats. Her boss, Alice Adelson instructed her to keep the cats away from the next-door neighbor Sebastian, the billionaire. An Alice cat, however, managed to escape from Stella's care and make the way to Sebastian's property, where caused her trouble. Stella is caught by Sebastian while trespassing his property.Sebastian informs her that she must keep the cat away or else he would punish her. Sebastian has already made the decision that he will going to own her and has stated that she will be responsible for the payment. But it's not in monetary value that he's looking for.