I've Already Confronted the Five Kage, and the System Just Arrived! - Chapter 245 - 246

An advertising director is reborn in 1988 Hollywood as an eighteen-year-old blond-haired westerner named Eric Williams.

Eight Thousand Years after the Glassing of Earth, Terran Descent Humanity has largely become a post-scarcity society based on consent and enjoying life. With the discovery of another ancient race beyond the “Great Gulf”, events and history collide to draw the Terran Confederacy into war against a hundred million year old empire that has always won and believes it always will. With allies and enemies of multiple species, the Orion Galactic Arm Spur will be wracked by warfare the likes of which have not been seen. Cracked, harried, wounded, and damaged, Terran Descent Humanity willfully throws itself against the universe itself. “The universe hates you and will take away everything you love, laughing while it does so.” - Terran belief.

Wang Yi gets a key, opening a door in 2022 will lead to 1982, and opening a door in 1982 will return to 2022.

Two very different great eras appeared before him:

Abundant dietary protection, developed industrial products, miraculous medicines, and explosive information, this is 2022.

Simple folk customs, rich wild resources, scattered antiques, and treasures of the age, this is 1982.

Traveling between these two eras, Wang Yi didn’t think much of it, he just wanted to live a good life.

- 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?”