Kojiro Nanjo known in "S" as Joe. A skilled skater and founding member of "S", he uses his unique build and stature to skate in an aggressive, movement-oriented fashion.

In "S", Joe seems to be a playboy who likes to charm and have fun with many women. 

Kojiro has a "papa bear" mentality and appears as a father figure to the younger boys, offering advice and noticing when things are off about them. He is very open-minded and kind towards the younger boys trying to help them whenever he can.