Dan Kuso (originally Danma Kuso) stands as the central protagonist across the original *Bakugan* series and its sequels. Introduced as a 12-year-old Wardington resident ranked #117 globally among brawlers, he rises to become the world's #1 brawler by the end of the first season. His age progresses through the series: 14 in *New Vestroia*, 16 in *Gundalian Invaders*, and 17 in *Mechtanium Surge*. He moves to Bayview during *Gundalian Invaders*, becoming Julie Makimoto's neighbor, and later relocates to Bakugan City in *Mechtanium Surge*. His consistent physical trait is brown hair topped with hexagonal goggles. His attire evolves seasonally: an initial red overcoat over a yellow sleeveless shirt, red trousers with black stripes, and blue-tongued sneakers; *New Vestroia* introduces a gold-trimmed long-sleeved overcoat with dark shoulder pads, a light blue sleeveless shirt, and white pants; *Gundalian Invaders* features a white-collared red jacket, elliptical goggles, and dark trousers; *Mechtanium Surge* shifts to a red jacket with a high black collar, jeans, and red-soled sneakers, occasionally including a sporting outfit with black and red trims. Passionate about Bakugan battles, Dan initially exhibits impulsiveness, overconfidence, and frustration during inactivity. Early battles rely on raw power, causing friction with his partner, the Pyrus Dragonoid Drago, culminating in Dan discarding Drago into a river after a loss—an act he later regrets. Defeat against Ryo teaches him the value of strategy, marking significant growth. He develops a strong sense of justice, frequently offering redemption to former adversaries like Spectra Phantom, Ren Krawler, and Team Anubias. Relationships involve frequent arguments with Runo Misaki, evolving into mutual care, close friendship, and eventual romance. Loyalty binds him to childhood friends Shun Kazami and Marucho Marukura, though stubbornness occasionally strains these bonds. Increased maturity emerges by *Gundalian Invaders*, shown when directing Jake Vallory to rebuild shield generators post-battle. Dan's journey begins inventing the Bakugan game with Shun using mysterious falling cards. His first major conflict pits him against Masquerade to prevent Bakugan banishment to the Doom Dimension. Reuniting with Drago, who accepts him as partner, Dan battles to stabilize the fractured dimension Vestroia and defeat Naga. This culminates in Drago sacrificing his physical form to become the new Perfect Core, restoring balance. Three years later in *New Vestroia*, Dan returns to aid Drago against the alien Vestals suppressing Bakugan consciousness. Joining the Resistance with Mira, Ace, and Baron, he masters the new brawling system and destroys dimensional controllers to liberate New Vestroia. He temporarily loses Drago to Spectra Phantom, recovering him after intensive training and a battle using Apollonir's borrowed power. Spectra later aids Dan against King Zenoheld’s Alternative Weapon System threatening Earth and Vestal. Post-crisis, Ren Krawler recruits Dan for the *Gundalian Invaders* conflict against Gundalian forces targeting Neathia’s Sacred Orb. During *Mechtanium Surge*, Dan and Drago grapple with uncontrolled powers bestowed by Code Eve, accidentally spawning the Mechtogan Zenthon during battles. This instability causes disqualification from the #1 rank in Bakugan Interspace after a match against Anubias. Mag Mel and Razenoid mentally influence Dan through Drago, causing reckless behavior endangering spectators, forcing Dan to relinquish leadership and depart the Battle Brawlers to seek control. He later returns, regains leadership, and helps prevent a dark future where Mechtavius Destroyer annihilates Bakugan City. Post-series narratives suggest Dan married Fabia and ascended as Neathia’s king, though these details originate from unofficial sources. His legacy endures as the universe’s strongest brawler, continuing adventures with Drago after resolving the Mechtanium crisis.