Zenjirou Tsurugi  

Jeremy Tsurugi, 剣 ゼンジロウ

Taiki's classmate who refers to himself as his "eternal rival" is a middle school student known for his expertise in kendo. He is said to be the strongest kenshi in Kōtō and has a talent for understanding machinery, thanks to his parents who are businesspeople in that field. After losing to an amateur Taiki during a tournament, he became determined to prove himself as the superior fighter and has been following Taiki around ever since. He also possesses skills in repairing Ballistamon.