Naruto: I Became a God by Salvaging the Difficulty Leveling System

Jiang Yuan traveled to the world of Naruto and became a ninja with no blood, no background, and was about to die on the battlefield. The moment he was pierced through the heart by a kunai, the [Salvage Intention System] was activated! As long as you make up for the regrets in Naruto, you will get rewards! Bite! The regret of successfully salvaging the 'Kijin' Zabuza, the reward: S-level Water Release: Roar of the Water Dragon God! [Ding! The regret of successfully salvaging 'Uchiha Itachi', the reward: Eternal Mangekyō Sharingan (version without side effects)! [Ding! The regret of successfully salvaging 'Jiraiya', the reward: perfect sage mode + god-level psychic beast! From then on, Jiang Yuan embarked on a path of "becoming stronger by saving people". When Pain made the world feel the pain, Jiang Yuan brought Jiraiya back from the underworld. When Uchiha Madara declared the Fourth Ninja War, Jiang Yuan resurrected the first and second generations, and conveniently brought back Madara's younger brother, Izuna. "Madara, what kind of fight are you going to fight? Your brother is calling you to go home for dinner!" However, when Jiang Yuan salvaged more and more "regrets", he discovered that these changed fates seemed to be leading the future of the entire ninja world to an unknown and more terrifying abyss... Who is the "unknown existence" hidden in the cracks of time and space?