Ileus: The Dark Prince - Chapter 44 - I Just… Know

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

“Finally, the owner has appeared. You read me.”The Archmage’s legacy, the Book of Truth.Binair Dalheim, a dropout of the Elfenbein Tower, accidentally discovers the Book of Truth.“I will awaken your magical talent. In return, complete me.”The dropout boy, whose dormant talent has been awakened, begins his journey to retrieve the Book of Truth as requested.

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!

- Description from Webnovel