Doomsday Descends: My Villainous Destiny - Chapter 4: The Lockdown Begins

After Reincarnating into Naruto World at the Warring State Era as an Uzumaki, Masahiko thought that he got a useless System. He lived for 48 years as a normal, below average Uzumaki Shinobi.

That changed when he finally knew how the system works the day of his 49th Birthday!

- Description from Novelupdates

Year 2056, in a city in the Yuan Jiang Su Jin area. On top of a ruined, shattered six story residential apartment sits a teenager wearing a combat vest, militaristic trousers, and alloyed battle boots. On his back is a hexagonal shield and equipped is a blood-shadow battle knife. He sits there silently on the edge of the roof. At this time, the sparkling sky was shining and there was a refreshing breath within the air that blew towards him. However, there was only silence within the ruined, deserted city, with an occasional howl that makes your heart skip a beat.

- Description from novelupdates

C-class mercenary. Started as a No Class, possessing nothing.

13 years of survival in the depths of the ditches.

I’ve managed to return to the beginning, but…

They are childhood sweethearts, they are engaged under the family’s scheme, and they have to live in the same room and sleep together.

That night, she was accidentally drunk, and he kissed her in a fascinating mood,. By accident, his “crime” was finally discovered, she accused him, but he said with a smile, “You are my wife, why can’t I kiss you?”

The two people’s daily routine is full of bickering, mutual hate.

He said that he disliked her. Actually, In his heart, he was extremely caring of her. When she was close to other boys, he was so jealous that he wants to tie her to his side and become exclusively his.