Was I even the strongest?

In the world where magic, martial art, Ki, Chakra, Guns everything you named. An orphan by the name of Jin started from nothing to become the emperor of a continent with his strength alone. He was really the strongest from his point of views. Until one day a dark figure showed up and killed him in a single breath. As he opened his eyes again. Time turned back to when he was nine which was 40 years ago. Read on how he lives his new life from his point of view, correcting his mistakes and unveil many secrets along the way. (the following story is a work of fiction, the following story contains many graphic scenes and could trigger many audiences, do not attempt to reenact the scenes from this story)