Jiro Oriza is a central character and a core member of the Tobita Club in Gekito! Crush Gear Turbo. He is the second Gear Fighter recruited to the team and becomes the closest friend and most trusted companion of the main protagonist, Kouya Marino. Jiro is introduced early in the series, first appearing as a guest at the opening ceremony for the rival Manganji Club, where he notably saves Kouya from a dangerous fall.

The foundation of Jiro's character is built on his dual passions for baseball and Crush Gear fighting. Before his involvement with Gear Fighting, baseball was his primary focus, and he served as a pitcher for a junior Little League team alongside a friend named Hiromi Taki. His baseball career was cut short due to a critical shoulder injury sustained during an important match, an event that forced him to step away from the sport he loved. This past trauma resurfaces later in the story when a similar injury threatens his ability to continue as a Gear Fighter. His entry into the world of Crush Gear came about during a camping trip when he was saved from a bear attack by the legendary Gear Fighter Alex Borg. Borg introduced him to the activity and gifted him his first Crush Gear, Raging Bull.

Visually, Jiro is recognized by his brown eyes and slick red hair, which features a spiky fringe parted in the middle of his forehead. His typical outfit consists of a dark baseball jersey worn over an orange undershirt, paired with khaki shorts and green sneakers, a look that reflects his enduring love for baseball. As a Gear Fighter, Jiro possesses considerable skill and confidence. He has a friendly and respectful nature that is well-regarded by his teammates, and he consistently demonstrates a strong sense of loyalty, particularly to Kouya and the Tobita Club. A notable aspect of his personality is a pronounced soft spot for Lilika, the deputy owner of the Tobita Club, and her presence often leaves him visibly flustered and affectionate. His baseball background heavily influences his fighting style, and he frequently adapts pitching techniques and motions to his Crush Gear battles.

Jiro's role in the story is primarily that of a steadfast ally and a key competitor for the Tobita Club. His journey involves joining the team after an initial refusal of Kouya's poorly written invitation letter and a subsequent victory in a Gear Fight against him. Throughout the series, he faces numerous opponents in various tournaments. In the Buthokan Cup finals, he has a significant reunion and match with his former baseball teammate, Taki, which ends in a draw. During the Asia Cup finals, he is defeated by Rai Shinomiya, who cleverly uses his sister's unconventional spin style to win. His personal rivalries also include Brad Fincher, whom he initially fails to defeat but later beats in the World Cup using a signature move he learned from Taki. A key relationship is his mentorship and friendship with Kouya, which is so close that Jiro uses practice matches against him to devise strategies for other opponents, such as U-YA.

His development is closely tied to overcoming the psychological and physical scars left by his baseball injury. A moment of personal crisis occurs when he re-injures his shoulder in an accident before the Manganji Cup, forcing him to confront his past trauma and fear of failure. Jiro's notable abilities as a Gear Fighter are channeled through his primary Crush Gear, Raging Bull, which he later upgrades to Raging Bullet. His signature special attack, which blends his athletic background with Gear Fighting, is known as the Hurricane Crush.