Married To The Cruel Crown Prince - Chapter 163 - Challenge You

After dying in the world of One Piece, he was reincarnated once again this time as Neji Hyuga. But fate was no kinder here. With his father dead and the cursed Caged Bird Seal looming over him, for his survival he made a ruthless decision....

In an era when the power of Fire Magic was considered to have reached its limit, one girl began researching nuclear fusion.

I had to take him home and raise him. There was no bathtub or a large basin at home, so I had to put him in the washing machine for the time being.

It was an hour later before I remembered it again, by which he had been washed extremely clean.

- Description from Novelupdates

He was a wealthy and mysterious financial backer who had appeared before her when she needed money the most. After the courtship, she took the money and left.