Jiromaru Takaba is the devoted younger brother of Ryo Takaba, constantly following him and expressing deep admiration. He fiercely defends Ryo against any perceived insult or mockery, showcasing their strong mutual reliance. Jiromaru uniquely addresses Ryo as "anchan," a blend of "oniichan" and "aniki."

In appearance, Jiromaru possesses long dark hair and brown eyes. His typical outfit consists of a pink shirt, brown gloves, long brown pants, and white-pink shoes. He completes his look with an orange headband on his forehead, mirroring Ryo's style. A notable speech quirk is his frequent use of "desu," consistently mispronounced as "dasu."

Jiromaru operates the customized Saber 600 Mini 4WD, the "Jiromaru Special," designed to resemble Ryo's Tridagger X. His vehicles often suffer significant damage during races. Early on, he attempted to gain an advantage over Retsu and Go Seiba by building an uneven track, but lost despite this作弊 attempt.

During the WGP season, Jiromaru stepped in for the injured Ryo in Episode 10. However, the scale of the competition triggered intense stage fright before the race. His interactions with Go Seiba are predominantly antagonistic; the two frequently clash and trade insults, often centering on their respective relationships with Ryo.

Background details include a March 25th birthdate and a hobby of cooking. Initially, the brothers lived a nomadic lifestyle, frequently seen camping in wilderness areas.