Death March kara Hajimaru Isekai Kyusoukyoku (WN) - Book 10 - 10-2. The Two Earldoms

A river song, triggered a legend of the rivers and lakes.
Tian Zun’s life motto: “My sword is the truth.”
Shen Lang’s life motto: “To serve people with morality, those who are dissatisfied are dead.”

- Description from uukanshu (translated)

Garou woke up in the world of Naruto, reborn as an ordinary civilian of the Hidden Leaf Village.To his shock, he discovered he suffered from the same limitation as Rock Lee: completely talentless in both ninjutsu and genjutsu. Worse yet, he belonged to the same generation as Naruto and the other members of the Konoha 12.But Garou wasn’t the type to quit. He knew that pure grind beats natural talent.Might Guy had already proven that much.However, unlike Guy, Garou had seen the end. He had watched the anime.He understood that taijutsu, as powerful as it was, always burned out like a firework, brilliant but brief.And this time, he had no intention of going out like that.Determined to break past the limits, Garou began creating his own techniques, pushing the boundaries of what a “mere” civilian could achieve.And the mysterious light orb in his mind granted him powers based on the influence his techniques had on others and the world itself.The world of Naruto would never be the same again.The grind doesn’t stop until the world bows before his fists.

Mysterious gates appeared all around the world a few decades ago. Beings emerged from the gates and brought disaster upon humanity. Humanity called them Demon Spirits. It wasn’t until the advent of Demon Suits and Demon Suiters that humans stood a fighting chance.For some perplexing reason, the world’s number one Demon Suiter, Li “God” Xiu abandons his identity to start over again as a newbie trial-taker. He enters the gates to participate in all sorts of trials, in a bid to seek out the reason that enticed his best friend into becoming a trial-taker.These trials weren't the run-of-the-mill dungeons, ranging from game sports (soccer, basketball, baseball, etc) to athletics. Just as fortune favors the brave, what would Li Xiu obtain on his quest?“Are you telling me he’s a greenhorn?” the other trial-takers frustratingly ask while watching Li Xiu's feats that prove why he's the number one Demon Suiter.

Brolin, the nine emperor of the Black Dragon Mountain Empire, accidentally obtained the system of the realm of the world, and began the legendary journey of the battles!

In the Naruto world, with his star power, he overwhelmed the shadow-level powerhouses, grabbing reincarnation, and becoming a ten-tailed person!

Fighting the mainland, he led a large group of lords, surrounded the ancient eight clan, and confronted the peak Dou Sheng!

Covering the sky, he broke into the restricted area, seized the emperor’s scriptures and immortal medicine, and called the Lord of the human universe to fight supreme, and the sky was falling apart!

In the eternal life world, he crosses all realms, and fights against the Supreme King of Stone with the attitude of eternal true God!

Immortal continent, he jewels Jiuyang, looks down on immortal ancient, strong sky!

The perfect world, he runs across the sea, suppresses the heavens, and the Zhunxian Emperor must retreat!

Thinking of the eternal world, he ascended to the realm of Supreme Hunyuan, the fifth step of the war, Bai Xiaochun!

Heaven and earth, this is an epic of the black dragon!

- Description from uukanshu