Baku Omori is a friendly and selfless 6th-year elementary student at Aibo Academy. He serves as the primary deck-builder for Team Balle du Soleil and maintains close friendships with classmates Gao Mikado and Kuguru Uki, his childhood friend, though they argue frequently. His easygoing nature leads him to build entire decks as thanks for small favors, like accepting a banana from Tetsuya Kurodake. Constant hunger heavily influences his behavior, causing cognitive decline or complete shutdown without food. He typically carries a toolbox-like card case and is perpetually preoccupied with deck construction concepts. Though quick to start fights, he possesses strong problem-solving skills and a tendency to dismantle interesting machinery. Despite frequent clashes with Gao, their bond remains solid. His deck-building philosophy centers on matching a deck's effectiveness to the owner's personal style. He initially revered his cousin Retsu Omori, who mentored his first deck build. However, after Retsu joined Disaster as "Gremlin" and advocated for decks that control fighters, Baku severed ties, dedicating himself to disproving Retsu's methods. During the ABC Cup, he reconciled with Gao after initially refusing to build decks for him, forming Team Balle du Soleil. He later adjusted Gao's deck to fix strategic vulnerabilities, enlisting Jin Magatsu to help convince Gao. Recurring implications of mutual romantic interest exist between Baku and Kuguru, though both vehemently deny it. During Gao's Dungeon World duel, their monster counterparts, Craftsman Baku and Sage Kuguru, performed a Link Attack while holding hands, causing visible embarrassment. When Baku fainted afterward, Kuguru expressed concern, but Baku attributed it to hunger, declaring he would "choose lunch over love any day"—prompting Kuguru to force-feed him bananas. In a pivotal confrontation, Retsu (as Gremlin) invited Baku to join Disaster, but Baku refused upon learning Retsu led Darkness Masterminds. Disturbed that Retsu taught him deck-building merely to use him as a pawn, Baku initially resisted adding Jackknife Dragon to Gao's deck, fearing imbalance. He relented after Gao's insistence, and Gao's victory over Retsu filled Baku with pride. Later, strategizing against Tasuku Ryuenji's Distortion Punisher!! card, Baku struggled until Retsu indirectly provided a solution during a cryptic exchange. Baku deduced that activating Roaring Slash!! Gargantua Punisher!! would trigger Distortion Punisher!!, allowing Gao's Dragon Return System to revive him at 2 Life and secure victory—a tactic Retsu simultaneously devised for Tasuku, resulting in a tie. Before Gao's rematch against Kyoya Gaen, Baku delivered an upgraded "Explosive Fang Dragon" deck, contributing to Gao's triumph. He later collaborated with Gao, Drum, and Kuguru to name an Impact card given by Tasuku. His only documented Buddyfight losses were against Kuguru (disguised as Sofia Sakharov) and Tetsuya Kurodake.