I'm in Zongman, if you mess with me, you'll die

Under the torture of an illness, Yang Jian was taken by the system to the world of Demon Slayer. In order to make up for the last words of his previous life. In this life, he is fearless, just to climb the highest mountain and see the most beautiful scenery in the world. Demon Slayer World: He is the psychological shadow of Muzan, and his powerful and unmatched figure makes him deeply afraid. Pirate World: He is the world's number one swordsman and a bounty hunter feared by all forces. Naruto World: His power is deeply imprinted in the eyes of the five major ninja villages, and Otsutsuki can only be silent under his indestructible iron fist and sharp blade... [New author, what's wrong,...