Bull Borgnine possesses a fragmented psyche divided into three distinct identities: a placid, guileless demeanor; a self-assured alter ego; and a ferocious battle-triggered berserker state. Each personality manifests physical changes—bluish-black hair and rounded eyes in his calm form, grayish-black locks with sharper features when confident, and crimson spiked hair during frenzied combat. His attire remains consistent: a yellow poncho, skull pendant, and forest-green mechanic’s overalls equipped with tools, symbolizing his progression from rogue to technical specialist.

Originally a enigmatic B-Daman thief, Bull abandons deceit after bonding with Yamato Delgado, embracing honorable competition. His wild persona synergizes with the Helio Breaker B-Daman, granting battle invincibility at the cost of post-transformation amnesia. Following Helio Breaker’s destruction, he redirects his talents to engineering, revamping allies’ gear like Yamato’s Cobalt Saber and crafting Chrome Raven for Gray, solidifying his indispensability as the group’s inventor.

The IBA Winners Tournament tests Bull’s resolve through external manipulation and internal strife, including mind control by Ababa of the Shadow Alliance, compelling him to combat Yamato. Freed from influence, he conquers challenges like the Five Field Trials, outmaneuvering foes such as Joshua and Goldo via tactical flexibility. His dynamic with Miss Karat evolves from resisting aid to forging mutual reliance, illustrating his gradual acceptance of collaboration.

Advancing his craft, Bull partners with Armada to pioneer cutting-edge B-Daman prototypes like King Rekuso and King Bakuso. Temporarily commanding the Neon City Army with the Helio Breaker-inspired Armada Special, he confronts peril during Marda B’s onslaught, enduring petrification before eventual recovery. Post-liberation, he persists as a resilient asset in collective missions.

By the second season, Bull’s serene identity prevails, tempered by diminished impulsiveness and fortified self-assurance. He pursues Strike Shots, weathers tournament defeats, and allies with Aqulas to dismantle threats, underscoring tenacity. His engineering expertise continues driving team success, maintaining equipment and innovating solutions without resorting to fractured personas.

Bull’s trajectory charts a metamorphosis from fractured loner to cohesive team pillar, harmonizing battlefield ferocity with mechanical genius. His redemption arc intertwines strategic combat contributions, mentorship under Armada, and hard-won self-integration, epitomizing perseverance and adaptive growth.