MTL - Dudu’s Diary - Chapter 17 Once she

Betrayed and left for dead, a soldier awakens in a world of knights and magic—but only one path is open to him.Hayden was once an elite soldier whose abilities were enhanced by the Ocularis Lens, a highly advanced mechanical eye technology.In this world that was filled with danger, Aura—a sacred energy that enhances the body and infuses weapons—is the mark of a true Knight, while magic is wielded by those born with the gift of sensing Mana.Hayden, however, is no mage. He doesn't have the ability to sense Mana, leaving him with only one option in order to survive: to become a Knight starting from a Knight's Academy!

He died on the wedding of the girl he had a crush on, after a long and successful career. After convincing Yama to send him back to the world, he decides to fix the areas in which his life went wrong. Realizing the lack of love and romance in his past life, he sets out to conquer the hearts of various women.

I became the childhood friend of the protagonist in a novel. The childhood friend who died from taking drugs.

A boy from 21st century Earth, met an accident and later was reborn in Naruto’s Ninja World.
He is born in Uchiha Family and becomes the useless brother of Itachi Uchiha and Sasuke Uchiha…. Let’s see how he changed the Naruto world.

- Description from Novelupdates