Chōji "Marucho" Marukura remains a foundational member of the Battle Brawlers throughout the series. Initially characterized by wealth, intellectual brilliance, and obedience to his parents driven by fear, his experiences with the team spur profound personal growth. He evolves from a sheltered child into a resilient, independent strategist, ultimately embracing his journey without regret. Personality assessments identify him as an INFP and Enneagram Type 6w5, emphasizing loyalty, analytical thinking, emotional sensitivity, and a strong sense of duty, sometimes manifesting as anxiety or indecision. Physically, Marucho possesses a small stature, distinctive blue hair, and a persistently youthful appearance. His attire consistently features blue, reflecting his Aquos attribute. Within the Battle Brawlers, Marucho serves as the primary strategist and tactician, leveraging deep knowledge of Bakugan mechanics. He mediates between impulsive Dan and reserved Shun, forming the core trio's "brain." His wealth supplies crucial resources like advanced technology and shelter, notably his mansion serving as a shielded base. Later seasons see him assume leadership during Dan's absences or internal conflicts. His journey features evolving Bakugan partnerships: - **Preyas**: His first Guardian Bakugan, noted for sarcasm and attribute-changing ability. It evolves into Angelo/Diablo Preyas during Vestroia's reclamation. Temporarily lost to the Doom Dimension, Preyas is rescued and remains a key partner, often competing with Elfin. - **Elfin (later Minx Elfin)**: Becomes his primary partner in *New Vestroia* after Preyas' capture. Met in New Vestroia's jungles, Elfin requires Marucho to prove himself before partnering. She evolves into Minx Elfin after receiving Attribute Energy from the Six Ancient Warriors. - **Akwimos**: His partner during *Gundalian Invaders*, initially a digital clone before obtaining the real Akwimos. Left on Neathia post-conflict. - **Infinity Trister**: Primary partner in *Mechtanium Surge*'s first arc, utilizing the BakuNano Silver Crosstriker and Mechtogan Accelerak. - **Radizen and Roxtor**: Partners in *Mechtanium Surge*'s second arc. Roxtor is borrowed from Mira Fermin. Radizen generates the Mechtogan Flytris, combining with Shun's partner for the Duomechtra fusion. Marucho's story spans critical conflicts: - **Bakugan Battle Brawlers**: Begins after moving to Dan's town, where Preyas crashes his party. He participates in pivotal battles, including recruiting Shun, losing Preyas to Klaus, reclaiming Preyas, and contributing to Naga's defeat. A key test involves confronting an illusion of his obedient past self, leading to self-acceptance. - **New Vestroia**: Joins the Resistance against the Vexos. After initially lacking an Aquos Bakugan, he partners with Elfin battling Mylene Farrow. Key moments include defeating Shadow Prove to open a portal, capture by Volt Luster, rescue by Spectra and Mira, victories with Shun in Gamma City, liberating Bakugan including Preyas from Hydron, and battling King Zenoheld's Alternative Weapon System. - **Gundalian Invaders**: Battles in Bakugan Interspace during the Gundalian-Neathian war. His record includes wins with Dan and Jake, losses to Stoica and Gill/Airzel, and participation in the final conflict against Emperor Barodius. - **Mechtanium Surge**: Confronts chaotic Mechtogan and antagonists like Mag Mel. Key events include battling Sellon and Anubias, using new Battle Suits from Mira and Runo, participating in fusions (Betakor, Duomechtra), and joining the final assault to stop Mechtavius Destroyer's destruction of Bakugan City, involving time travel to avert a dark future. Relationships define his character. He shares a deep, brotherly bond with Dan Kuso and Shun Kazami, forming the core trio. His interactions with Bakugan, especially Preyas, show mutual loyalty and humorous friction. He maintains respectful ties with allies like Mira Fermin and Baron Leltoy. His familial dynamic involves distance from his parents, mitigated by butler Kato, who later works solely for Marucho's father.