Naruto: From the Start, a Chunin in the Uchiha Clan

Uchiha Tong transmigrates to the Naruto world and unexpectedly obtains a fragment-collecting System. After enduring hardship for three years, he finally gathers enough Sharingan fragments to evolve into the Mangekyō. He conceals his identity and takes part in organizing the Uchiha Clan Massacre, gathering fragments during the ensuing battles and successfully awakening the Eternal Mangekyō Sharingan. He then builds up his strength and ventures into the other ninja villages, becoming the most powerful BOSS in the Shinobi World...