Years pass and Jin is reincarnated as a baby. This time it is different from the previous one. A book next to him explains what has happened in the last 15 years.
Monsters have taken over the world and only 30 percent of humans survived. Some of them have built underground cities, while others have built sky cities with zeppelins.
However, monsters rule and make people work as slaves. In the place where Jin is located, people escaping from monsters have formed a tribe.
While examining the babies, the tribe's leader notices Jin and realizes that he is different from the others. However, he does not reveal this, thinking that Jin will become a warrior who will try to save humanity in the future.
As Jin grows up, he changes his name to Nijin. This is because he used the name Jin in his early and later life. Due to his second reincarnation, his name became Nijin.
Nijin is stronger than her peers and has received three times as much training. However, the system noticed that it no longer turned on and the tattoo was gone. He now has some control over his shadow powers, and the experiences from his previous lives are still present.
At the age of 18, all the warriors spread out across the world and set out on a journey to save humanity. Nijin was separated from them and there were hologram phones where technology was developed at that time.
He accesses the internet through these phones and realizes that he needs to find a blacksmith. A descendant of the legendary blacksmith lives, but monsters make him a slave and make swords all day long. Nijin goes to save him.