Rouga Aragami emerges as a major character, initially an antagonist who evolves into a supporting role across multiple seasons. An 8th-grade student at Aibo Academy and its top Buddyfighter, his early persona radiates strictness, seriousness, and ruthless focus on victory. He disrespects opponents by refusing to use their names and perceives defeat as humiliation demanding vengeance. This stems from a childhood scarred by extreme poverty in a harsh environment where survival was paramount, teaching him that names and attachments were pointless burdens.

During this period, he encountered Kyoya Gaen. Kyoya offered friendship, which Rouga secretly cherished while outwardly denying any need for companions. This fragile loyalty propelled him into the villainous organization Disaster under the alias "Wolf," adopting a transformed appearance with long silver hair and a mask, wielding a Dark Core Gadget. As Wolf, he deploys a Danger World deck centered on Armorknight Cerberus, executing aggressive tactics that rapidly deplete opponents' life points, often ignoring their safety.

Despite his allegiance to Disaster and merciless methods, Rouga upholds a fierce sense of honor. He openly condemns cheating or underhanded tactics, scorning a teammate’s Hate Card as a "cheap win" and urging an opponent planning intentional defeat to keep fighting. This moral complexity surfaces even during his antagonistic phase.

A pivotal shift begins in his intense rivalry with Gao Mikado. Initially seeking revenge after a loss, Rouga unexpectedly finds joy in their rematch, unleashing genuine laughter—a rarity noted by his buddy monster. Though rejecting friendship with Gao, he acknowledges him as a rival, marking the start of subtle internal change.

His loyalty to Kyoya and Disaster becomes a core conflict. Facing accusations of following a king out of fear, he confronts these claims during a critical duel against Zanya Kisaragi. Attempting to sway Kyoya from his destructive path, Rouga hopes to salvage their bond. Kyoya coldly reveals their friendship was a ruse for obedience and banishes him from Disaster. This betrayal inflicts profound shock and anguish, forcing Rouga to reassess his purpose.

Post-betrayal, he undergoes gradual growth. He consciously uses an opponent’s actual name, aids in foiling Kyoya’s schemes, and transfers to Sengoku Academy. Though socially awkward and still grappling with friendship, he wields power more responsibly. He assists the Omni Lords in sealing the demonic entity Yamigedo during Hundred, earning deities' respect like Grangadez, whom he integrates into his evolving Danger World deck. His strategy shifts from Armorknight Eagle to Cerberus "A," later embracing a Tyrant focus with Fang Spear Axe, Ogar Demon Slay, and Tyrant Cerberus "Violence Gazer!" in Triple D.

His relationship with Kyoya remains strained. In Triple D, another attempt to dissuade Kyoya from godhood ambitions results in Rouga being forced into a Buddyfight: defeat means becoming Kyoya’s servant. After an off-screen loss, he reluctantly resumes the Wolf persona and mask. Official materials indicate their dynamic reaches a more stable, complex understanding by Triple D’s conclusion.

Throughout his journey, rivalries evolve into respect. Initial contempt for fighters like Tetsuya Kurodake transforms into acknowledging warriors such as Kiri Hyoryu, whom he recruits for training and later shares mutual respect with following Kiri’s Omni Lord revelation. His core motivation shifts from an obsession with victory and loyalty to Kyoya toward a nuanced existence involving reluctant alliances, confronting past trauma, and wrestling with connection despite ingrained self-reliance.