Naruto: Reborn with Kaguya Powers - Chapter 2: Kumogakure and A.

After the divorce, Gao Jun discovered that the persona of the wealthy single lady had collapsed.“Madam, please stop confessing your feelings to me,” he said.“You know I'm not someone who takes things lightly.”

He—an enigmatic and cold-blooded soldier with a mysterious background.
She—a ruthless and bloodthirsty spy.

I was a failed experiment

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates