In the Transformers: Energon narrative, Roadbuster is the Japanese designation for the character known elsewhere as Ironhide. He is a young and enthusiastic Autobot soldier, eager to prove his worth on Optimus Prime's elite team. His overeager nature is often noted by his comrades, though his intentions remain positive, driven by a desire to demonstrate his capabilities and gain acceptance. His skills earned him both his position and the honor of a Combination Spark. Roadbuster possesses a strong tendency to idolize figures such as Hot Shot, Rodimus, and even the Decepticon Scorponok at one point. He is highly defensive of these idols and becomes upset if their methods or orders are questioned. He maintains a pronounced wariness toward Decepticons, including those allied with the Autobots. He forms a key partnership with the energon-sensitive human Kicker Jones. Their interactions are frequently strained and conflictual, yet underpinned by genuine mutual care. Roadbuster often employs the Energon Saber in battle. His background includes memorizing Rodimus's speeches while in school on Cybertron. As a rookie, he was in training after the Unicron Battles when the Terrorcon invasion began. He first encountered Kicker during a battle at Ocean City, and despite initial mutual disapproval, Optimus Prime permanently paired them as partners. A recurring arc involves his struggle with overconfidence and learning from its consequences. During a battle at Lunar City, he recklessly handled raw energon, causing an energy backlash that damaged him and allowed Terrorcons to escape with stolen energon. He felt guilt over this, though Optimus Prime noted that Kicker's absence as backup was a factor. Later, during a mission to Blizzard City, he supported Kicker in overcoming a fear of the dark. He develops by learning the value of precision and efficiency in combat from his comrade Inferno, moving away from indiscriminate fire. He applied this lesson to make a crucial long-range shot that destroyed Jungle City's energon mines to prevent them from falling into enemy hands. Supplemental material identifies him as the older brother of Ironhide, another Autobot. In this context, he is a tough war veteran who has survived multiple conflicts and takes on a mentoring role for his brother.