Espa Roba
After you beat Bonz for the first time, go to the center alleyway through Clock Tower Square, and you will see Espa's little bros, which you may battle. After beating the two of them along with Espa, Espa will ask you a question. Answer no and he will stay so you can duel him anytime. If you say true, you will never see him again in the game, unless you start a new file.
Darkboarder_77
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