MTL - Uzumaki Naruto is a Traitor - Chapter 147

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

When crossing over to multiple books, Ren Shuhan found that every protagonist Shou was waiting for him to start chasing them in the crematorium.

“Don’t waste your time waiting,” He advised sincerely, “There are more 0s than 1s, so I’m not going to chase someone that is not interested.”

The protagonist Shou (sneering): Oh, there will be a day where you’ll lick the ground I walk on.

After waiting and waiting…

Ren Shuhan: “This is the wedding invitation for my childhood friend and I’s wedding.”

On the wedding night, Ren Shuhan removed the veil: “Baby, I’ve come to marry you.”

“Don’t you know that life is nothing but a play where you are the male lead and I am just a supporting character?”

“I know, but I don’t care.”

He was smiling, but Jiang Qingyue wept.

- 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.