Dan Kuso, the central protagonist of the Bakugan series including its fourth season Mechtanium Surge, is approximately 17-18 years old and operates from the Battle Brawlers Headquarters in Bakugan City. His appearance evolves significantly: in the first arc, he sports a red jacket featuring a black high collar and shoulder pads over a white and blue T-shirt, jeans, and red-soled sneakers, with rectangular goggles. The second arc sees him transition to a red jacket with white shoulders, dark red jeans, and black fingerless gloves; he also occasionally wears black sportswear with red trims during morning jogs. Personality-wise, Dan retains his core impulsiveness and competitiveness but demonstrates notable maturity compared to earlier seasons. He aspires to uphold his reputation as a top brawler but grapples with self-doubt when his partner Drago's powers spiral out of control. While still prone to frustration and overconfidence, he exhibits greater strategic thinking and responsibility, especially when Bakugan City faces existential threats. His loyalty to friends remains unwavering, though tensions flare with Shun and Marucho over his handling of Drago's instability. Dan confronts unprecedented challenges this season. After Drago evolves into Pyrus Fusion Dragonoid, exposure to Code Eve's energy grants immense power but causes destabilization. During Bakugan Interspace battles, Dan and Drago involuntarily spawn the destructive Mechtogan Zenthon, leading to arena destruction, public backlash, and Dan's disqualification as the #1 ranked brawler after a loss to Anubias. The psychological toll manifests as nightmares featuring Mag Mel, a mysterious armored entity demanding surrender. To regain control, Dan travels to New Vestroia with Drago, reconnecting with Preyas for intensive training. This process rebuilds their bond, stabilizes their power, and enables them to tame Zenthon. Returning to confront Mag Mel and his partner Razenoid (revealed as Emperor Barodius and Phantom Dharak), Dan temporarily partners with Reptak, forming the Pyrus/Haos Aeroblitz Baku Sky Raider alongside Reptak's partner Gunz Lazar. He also utilizes Bakugan Battle Suits like Pyrus Doomtronic and Defendtrix, provided by Mira Fermin. In the season's second arc, Dan co-founds Bakugan City to foster human-Bakugan coexistence. This peace shatters when rogue Nonet Bakugan and Mechtogan from the Doom Dimension, allied with the entity Wiseman, attack. Dan coordinates defense efforts alongside Shun, Marucho, Julie, and Mira. A critical moment occurs when Mechtavius Destroyer annihilates the city, killing Runo, Julie, and Mira; this catastrophe is averted when Dan, Shun, and Marucho utilize the Current of Time to reverse events and permanently destroy Mechtavius Destroyer. Key relationships define his journey: his central partnership with Drago is strained by power instability but ultimately fortified through mutual trust. He clashes with Shun over battle strategies but relies on their enduring friendship during crises. Runo Misaki re-enters briefly, delivering Battle Suits and temporarily partnering with Haos Aerogan. Figures like Spectra Phantom and Mira Fermin provide crucial support against the Chaos Army and Nonet threats.