Re:Zero Kara Hajimeru Isekai Seikatsu - Operation Kokkuri

After graduating from college and unsure of where to go, Zhou Wang accidentally activated the “Game of Life” system while playing a video game, turning his life into easy mode from then on.We can't return to the past, but we can always change the way we live.Growing through indulgence, advancing with a carefree spirit....Zhou Wang: “This time, I'll only be the winner.”

Witnessing her boyfriend cheating on her with her bestie, Shiyao was so angry that she went to a pub for fun and met a man, who was really a piece of work. After a crazy night she fled away, but was embarrassed to know that the man she slept with was her boss You Ze.
Jesus, give her a break!

- Description from Novelupdates

Roy’s life was nothing special. The only thing commendable was the last few moments when he saved a mother and her child from a drunk driver.
…
It’s really an egg! Damn it, what kind of monster have I become? Did I fall into Hell instead of making it to Heaven??
Join Roy as he ventures through various worlds with the Custom Made Demon King System—a system that allows Roy to draw anything he can imagine and create it through exchanging souls!

An Individual from Earth finds themselves in the Shinobi World, equipped with a Scientific System. From that moment, he delved into scientific research far ahead of its time.