In a world of ninjas and chakra, Yamanaka Kei lives with a secret: he possesses memories of another life. After nineteen years of waiting, a mysterious system finally activates within him.With the Third Great Ninja War looming on the horizon, Kei must navigate the dangerous shinobi world while uncovering the full potential of his system. As he bonds with his students and reconnects with old friends, he contemplates how he might use his abilities to change the world.Perhaps someday, he might even discover a trait that allows him to travel between dimensions.--------------------I don't own Naruto. All original rights belong to the main creator: Masashi Kishimoto.Warnings:- AU- very powerful MC- system- other worlds