Soul-swapping:Imperial concubine rebirth - Chapter 648

Going for a swim, she ends up in an ancient wild Beast World and ends up being brought home by a handsome wolf.
She wants to stick to the handsome wolf, stock some salt, farm some land, look at some handsome men and grow old like that, but the handsome wolf pounces on her every day.
What? He wants her to have babies?
NO~ NO~ NO~ There is no happy ending to interspecies marriages, hurry and let go of me handsome wolf~

- Description from Novelupdates

Hitoshi's life sucked and then a truck made it even worse.But death wasn't the end. He wakes up in a fantasy world as a slave, expecting more of the same bad luck. Then a maid from the super-rich Aoi family buys him to work at their huge mansion. Finally, a break, right?Wrong.Sure, the mansion is amazing. The food is great. And yeah, the Aoi family treats him way better than he expected. But something's... off. Why do they watch him so closely? Why does everyone get weird when he smiles? And why do bad things keep happening to anyone who gets too friendly with him?Hitoshi just wants to be a good servant and make everyone happy. He doesn't realize that his kind heart and helpful nature are stirring up something dangerous within the Aoi household. In this new world, his greatest talent might become his biggest problem.They say no good deed goes unpunished. In the Aoi mansion, every act of kindness pulls him deeper into a web of obsession he never saw coming.“Reincarnated into Madness: Yandere Family's Unwanted Slave” is a story about second chances, magic, and what happens when being too nice leads to some seriously creepy consequences.

The main character is reborn as a character from a game he played in his previous life. This character falls into ruin along with the villainess, spending the last of their years together. A man named Kururi Helan.

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