Dan Kuso is the central protagonist across all four seasons of the original *Bakugan* anime. Beginning as a passionate but reckless 12-year-old Pyrus brawler obsessed with winning, his initial impulsiveness sparks conflict with his partner Dragonoid (Drago), culminating in Dan throwing Drago into a river after a costly victory that banished Bakugan to the Doom Dimension. A subsequent loss to Ryo forces Dan to confront his shortcomings, leading to reconciliation with Drago and the start of his strategic development. This growth enables him to compete against higher-ranked opponents and ultimately achieve his goal of becoming the top-ranked brawler by the first season's end. At age 15 during *New Vestroia*, Dan travels to the Bakugan homeworld to aid Drago and the Resistance against the Vestal invaders, the Vexos. He adapts to the new brawling system, forms alliances with Mira, Ace, and Baron, and faces significant challenges, including Drago’s capture by Spectra Phantom. This loss triggers a deep emotional crisis, resolved only after intensive training and a pivotal battle alongside the Legendary Soldier Apollonir to reclaim Drago. Key developments include mastering the "Perfect Core" ability, collaborating with former enemy Spectra (revealed as Keith Fermin) to create Drago’s JetKor Battle Gear, and leading the final assault that destroys King Zenoheld’s Alternative weapon system, saving both New Vestroia and Earth. Relocating to Bayview at age 16 in *Gundalian Invaders*, Dan befriends Jake Vallory and initially trusts the Gundalian spy Ren Krawler. Upon uncovering Ren’s deception and the Gundalians' true role as aggressors against Neathia, Dan allies with Princess Fabia Sheen. His tactical skills mature further during this interstellar war, navigating betrayals and obtaining powerful assets like the Dragonoid Colossus. Drago undergoes multiple evolutions (Lumino, Blitz, Titanium Dragonoid) fueled by conflicts such as defeating Phantom Dharak and receiving Code Eve’s power. A temporary transformation into a Neathian castle knight demonstrates his adaptability, though he reverts to his standard attire after the conflict. In *Mechtanium Surge* (ages 17–18), Dan grapples with destabilizing powers granted by Code Eve, which forge a psychic link to the antagonist Mag Mel. This connection causes hallucinations, loss of control, and the accidental spawning of the destructive Mechtogan Zenthon, leading to his disqualification as Bakugan Interspace’s top brawler after a match against Anubias. His overconfidence strains relationships with teammates like Marucho and Shun, prompting temporary self-imposed exile for training to master his abilities. Post-training, he regains stability and partners temporarily with Reptak for aerial battles using the Baku Sky Raider Aeroblitz. The series concludes with Dan preventing the annihilation of Bakugan City and the deaths of allies like Runo and Julie by utilizing the Current of Time to undo Mechtavius Destroyer’s future. Character relationships define key aspects of his journey: a deep bond with Drago, marked by mutual growth and the unique "Switch Code" destiny link; romantic tension with Runo Misaki, culminating in a date after saving Vestroia; rivalries evolving into alliances, notably with Masquerade (Alice Gehabich) and Spectra/Keith; and familial moments with his parents—his mother Miyoko’s yoga enthusiasm and father Shinjiro’s pudding obsession mirroring Dan’s own exuberance. His personality evolves from brash and impatient to a more measured leader, though he retains core traits like impulsiveness and a strong sense of justice, often offering redemption to former enemies. Visually, Dan’s appearance changes each season, notably his iconic goggles (hexagonal, elliptical, then rectangular) and outfits ranging from red jackets to specialized armor in Gundalia and darker jeans in Mechtanium Surge’s later arc.