Naoki Ishida, a student at Miyaji Academy, begins as a reclusive figure whose withdrawn demeanor casts him as an unlikely bully in the eyes of peers. A childhood memory of witnessing Aichi Sendou’s bullying without intervening fuels his resolve to shield others—manifested in defending Aichi from vandalized club flyers and protecting Kourin Tatsunagi from aggressive fans, revealing a fiercely loyal core. His cardfighting journey ignites after crossing paths with Aichi at Card Capital, where he obtains a Narukami Trial Deck. Early battles expose a fiercely offensive strategy, often leaving defenses vulnerable. Initial defeats by rivals like Shingo Komoi and Toshiki Kai spur refinement of his tactics, transforming his rivalry with Shingo into a partnership marked by mutual respect. His deck evolves to prioritize field control and "Eradicator" unit synergy, integrating cards like Gauntlet Buster Dragon and Tempest Bolt Dragon to dismantle enemy formations and escalate aggression. A pivotal clash with Link Joker’s corruption inverts his personality temporarily. Restored, he liberates Miyaji Academy by defeating reversed fighters—including Shingo and Maki Nagashiro—showcasing newfound resilience and leadership. When external forces erase memories of Aichi, Naoki reignites his resolve through clashes with adversaries like Leon Soryu and Mores, contributing to Aichi’s rescue. Later, he joins global efforts like Plan G, uniting with allies to thwart threats such as Ryuzu Myoujin’s GIRS system manipulation. His role expands to mentoring newer fighters, embodying themes of solidarity and tenacity. His battle cry—"Rip ’em up! My avatar!"—mirrors his fiery passion, while relationships evolve from isolation to camaraderie, notably his respectful dynamic with Misaki Tokura, whom he addresses as "Boss." Sporting red spiked hair and piercing yellow eyes, he alternates between his academy uniform and casual green jackets. Across adaptations, his arc traces a journey from outsider to integral team player, anchored by fierce loyalty to allies and relentless pursuit of mastery in cardfighting.