Emerging from Junk Island in Vestroia after the Great Collision, Sharktar became the new Guardian Bakugan for Shun Kazami following the hibernation of Shun's previous partners. He joined during a period of unstable gates allowing new Bakugan to cross between Earth and Vestroia.

Sharktar possesses a blue, shark-like form equipped with legs, arms, a tail, and razor-sharp teeth. His personality initially mirrored a Marine Drill Sergeant: aggressive, loud, and intensely disciplined. This clashed sharply with Shun's reserved and strategic nature, as Sharktar believed Shun needed to "toughen up." He relentlessly barked orders, even at non-combatants, reflecting his obsession with battle readiness.

Unlike other Junk Island Bakugan, Sharktar immediately embraced battling with seriousness and unwavering loyalty to Shun, prioritizing their partnership despite differing styles. His combat prowess excels in aquatic environments, leveraging abilities like "Echo Search" for echolocation targeting, "Armored Defense" to nullify attacks, and offensive moves such as "Chomping Tornado" or "Whirling Tide."

Through their partnership, Sharktar gradually tempered his harshness under Shun's calm leadership. He developed teamwork skills and genuine concern for allies, notably shielding Drago from Surturan, signifying loyalty extending beyond Shun. Though tied to Junk Island Bakugan who treasured human artifacts, his journey led to greater responsibilities, including guardianship of the Aquilia Artifact and the Aquos Crystal.

His arc culminated in a balance between inherent fierceness and learned composure, marking him as a resilient and adaptable guardian.