City Ninja

This is an era where ninjas are rampant "My surname is Yu and my name is Ban. I am a time traveler and I have a plug-in." "My system allows me to unlock all the skills of each character!" "When I slapped Uchiha Sasuke until he smiled from ear to ear..." "My system says... It can only automatically unlock skills corresponding to the character's age." "Fortunately, I'm almost sixteen, and I'm still smiling from ear to ear!" This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.