Gaito Kurōzu emerges as a reclusive, fiercely determined figure fixated on validating his strength through relentless victory. His icy exterior and habit of rebuffing others mask an unshakable conviction in his destined supremacy, solidified after forging a partnership with the Black Death Dragon, Abygale. Their alliance sparks when he saves her following a clash with Azi Dahaka in the Darkness Dragon World, igniting a shared quest for dominance.

Initially, his combat tactics prioritize obliterating opponents’ decks and exploiting discarded cards with tools like Death Dragon Sickle and the Impact Monster "Vanishing Death Hole!" Over time, his strategy matures—adopting the Dragon Force "Style of Retaliation" to master counterattacks, then shifting toward survival-centric maneuvers. He deploys the Impact "Death Count ~Requiem~" to clinch victories after enduring three turns, bolstered by allies such as Black Crest Dragon, Zillowzest.

A seismic shift follows his inaugural defeat against Gao Mikado, shattering his confidence and compelling him to reassess his win-at-all-costs philosophy. This humbling sparks gradual emotional evolution, fostering unexpected alliances with former rivals like Tasuku Ryuenji to combat threats like Kyoya Gaen and Dragon Drei. His bond with Abygale transforms from pragmatic alliance to profound mutual trust, anchored in shared purpose.

Beneath his stern facade lies a complex individual: he avoids crowded spaces, harbors an aversion to cats, and secretly mentors younger Aibo Academy students, revealing latent compassion. His arc culminates in a nuanced understanding of strength—one valuing allies and integrity as much as triumph.

Later, as an undercover Buddy Police operative, he synthesizes past tactics into adaptable contingency plans while refining his Dragon Force prowess. Confrontations with foes like J Genesis and Kyoya highlight his metamorphosis from solitary combatant to strategic leader, blending calculated aggression with hard-won wisdom.