Jiromaru Takaba, born March 25, is Ryo Takaba's younger brother. He possesses long dark hair and brown eyes, typically dressing in a pink shirt, brown gloves, long pants, and white-pink shoes while sporting an orange headband identical to his brother's.

Jiromaru deeply admires Ryo, following him everywhere and affectionately addressing him as "anchan"—a fusion of "oniichan" and "aniki." He fiercely protects Ryo, reacting defensively to any perceived insults against him. His speech frequently features the mispronunciation "dasu" instead of "desu," and cooking is among his hobbies.

He regularly clashes with Go Seiba, exchanging taunts often centered on Ryo. Jiromaru races a customized Mini 4WD dubbed "Jiromaru Special," which echoes the design of Ryo’s Tridagger X. His cars frequently suffer damage during races. In the WGP season, he substitutes for an injured Ryo, battling intense stage fright before the race due to the event’s magnitude.

During the movie "WGP Bousou Mini Yonku Daitsuiseki," Jiromaru aids Ryo and the TRF Victorys in pursuing the runaway "Gun Bluster" car, evading traps and supporting the team’s mission to capture it.