Baku Omori is a sixth-year elementary division student at Aibo Academy, classmates with Gao Mikado and childhood friends with Kuguru Uki. He acts as the professional deck-builder for Team Balle du Soleil, meticulously constructing and refining decks for team members. Baku possesses a generally friendly, easygoing, and selfless personality, yet is defined by an intense, constant hunger; without food, his cognitive and physical functions slow drastically, sometimes leading to fainting. He carries a toolbox-style card case and maintains deep focus on deck construction principles. He firmly believes effective deck design must integrate a player's personal preferences and playstyle while ensuring competitive strength. This philosophy directly opposes that of his former mentor, Retsu Omori (later Gremlin), whom Baku initially idolized. Retsu taught him to build his first deck in their youth, but their relationship fractured when Retsu joined Disaster and advocated using decks to control fighters. Baku rejected this approach, actively working to prove Retsu's ideology wrong. Their conflict peaked when Retsu, as Gremlin, attempted to recruit Baku into Disaster; Baku refused and later overcame Retsu's psychological manipulation during Gao Mikado’s duel against Tasuku Ryuenji. In that duel, Retsu claimed Baku couldn't counter "Distortion Punisher!!", but Baku realized Retsu's taunt contained a clue, enabling him to devise Gao's winning strategy: activating "Roaring Slash!! Gargantua Punisher!!" to trigger the Dragon Return System revival effect. Baku's development includes recurring hints of mutual romantic feelings with Kuguru Uki, though both consistently deny this. Their Dungeon World counterparts, Craftsman Baku and Sage Kuguru, performed a Link Attack while holding hands during a buddyfight, causing significant real-world embarrassment. When Baku later fainted from hunger, Kuguru showed visible concern before force-feeding him bananas after he declared he would "choose lunch over love any day." Kuguru also hugged Baku without protest when Gao defeated Kyoya. Throughout the series, Baku’s deck-building expertise proves instrumental in the team's victories. He resolved early disagreements with Gao by reconstructing Gao’s deck to fix strategic vulnerabilities, assisted by Jin Magatsu. He built multiple new decks for Gao upon Drum Bunker Dragon’s return and provided critical adjustments before Gao’s rematch with Tasuku and final duel against Kyoya. His technical contributions consistently support the team, reinforcing his role as both strategist and emotional anchor. Baku maintains a close, though argumentative, friendship with Gao, frequently clashing but ultimately reconciling through shared goals. Occasional impulsiveness leads him to disassemble machinery out of curiosity, and his loyalty to his principles remains a defining trait, particularly in rejecting Retsu’s methods. His recorded buddyfight matches include losses to Kuguru (under her alias Sofia Sakharov) and Tetsuya Kurodake.