Kotarou's nickname is "Kotarou the Runner".  He's a master of defensive battles, and minimizing losses when things turn bad.  His quiet, unassuming nature and the way he fights make him less likely to stand out than his other friends.  However, if he was put up against a real foe, someone who he couldn't beat unless he gave up on running, you might just learn his true name...
Then is this the Zaku-Zaku scam I've 
been hearin' about? You won't fool me!
إذًا فهذه هي خدعة زاكو-زاكو 
!الّتي سمعتُ عنها؟ لن تخدعني
Ah, ¿es esa estafa de Zaku?
Então isto é aquele golpe do Zaku-Zaku
 que andam dando? Você não vai me enganar!