Law of the Devil - Chapter 15

As a transmigrator turned extraordinary creature of the human race, he found the world to be more colorful than he had imagined.To more easily access everything this new realm had to offer, he first needed a special resume. Then, he had to find the right place in a city perennially shrouded in fog to fill out an application, and the last and most critical step...— was to kill a chicken or catch a mouse.

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.

A great demon king who came from another world to conquer Earth. To save the Earth, Li Luyou could only first take care of this great demon king… a little girl proclaiming herself Her Imperial Princess.

- Description from Novelupdates