Magic Industry Empire - Volume 1 Chapter 11 - Buying a slave

The protagonist travels through Shu Mountain and becomes a demonic dragon guarding the heavenly book in Dinghu Peak.

Doomsday comes, and human beings enter the heavenly world.
Ten years later, Yang Chen, who was betrayed tragically, returned strongly with the Tianyu bug. In this life, he vowed to make the betrayal pay the price. He has a powerful bug bonus, just like an open hang. Frightened to hear…

- Description from novelbuddy

Traveling to the world of Hokage, Kamiyo Colt witnessed the chaos of the Nine Tails firsthand.Without any special powers initially, he planned to develop quietly and survive until the Infinite Tsukuyomi. However, when he first trained his Chakra, his system finally activated.The system's rules were simple:By healing others, he could gain random attributes and skills.“Heal Uzumaki Naruto to receive pure Ashura Chakra!”“Heal Uchiha Shisui to gain his bloodline talent!”“Heal Sasuke Uchiha to obtain pure Indra Chakra!”In this way, Colt steadily developed his abilities over more than ten years.During the Fourth Ninja World War, when the ninja coalition saw him suddenly knock out the Six Paths Madara with a single punch, he looked innocently back at them.“What? I'm a medical ninja. Doesn't it make sense to defeat him with one punch?”