The First Magic World War - Chapter 657 - 622, New Weapons, New War

Leiyin accidentally crossed into the One Piece World, and accidentally obtained the Naruto System.

Chu Yang, the Ninth Master of the Nine Tribulations Sword, sacrificed almost everything he had for the sake of improving his martial arts, including the love of his life. After spending three years locating the fifth fragment of the Nine Tribulations Sword, he was ambushed by all sides at that very place. Mortally injured with no means of escape, Chu Yang executed a sacrificial technique by plunging the Nine Tribulations Sword into his very own heart. “With the blood of my heart, ten thousand tribulations will collapse!”

After witnessing the death of all his ambushers, Chu Yang’s vision began to darken. At a distance, moments before his death, he saw the mastermind who had plotted his downfall — Mo Tian Ji. With that, his eyes finally closed.

However, with a start, Chu Yang once again awoke to find that he had returned to when he was sixteen years of age! Furthermore, the Sword Spirit of the Nine Tribulations Sword now resided within his Dantian, the energy center of his body! From that very moment, Chu Yang would then begin to right all of his past regrets, and carve his very own legend by fulfilling his destiny as the final Master of the Nine Tribulations Sword, and defeating the Heavenly Devils beyond the realm of the Nine Heavens Continent.

- Description from novelupdates

An ordinary student accidentally traveled into an other universe and became the king of a small kingdom. He had gotten a “Cheating Code” of life and was able to complete something extraordinary. This is the story about a king that was able to conquer continents and leave behind him an ultimate legend that will be recited between every generation to come.

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