Nathan Seymour, known by the hero alias Fire Emblem, is a NEXT operating in Stern Bild City. As the president of Helios Energy, his own sponsoring company, he occupies a unique position among the heroes, combining corporate leadership with active duty. His background is marked by early struggles with societal expectations; from a young age he faced bullying and rejection due to his feminine interests and his attraction to men. These experiences shaped him into a resilient and self-assured adult, though traces of that past pain remain beneath his confident surface.

In personality, Nathan is flamboyant, expressive, and unapologetically authentic. He carries himself with a bold, theatrical flair that makes him one of the most visually striking heroes in the lineup. He is also highly intelligent and observant, often using his sharp insight to read situations and people. Despite his playful and sometimes teasing demeanor, he is deeply caring and empathetic, frequently acting as an emotional anchor for his fellow heroes. His motivations are rooted in a philosophy of self-acceptance and individuality; he believes in living freely and inspiring others to embrace their true selves without fear of judgment.

Within the story of Tiger & Bunny the Movie: The Beginning, Nathan plays a supporting role, providing both tactical assistance and social glue for the hero team. He is not a central figure in the plot, but his presence adds depth to the ensemble. He engages in lighthearted banter with Kotetsu Kaburagi (Wild Tiger), often flirting with him in a teasing manner, and shows a willingness to offer guidance to less experienced heroes such as Karina Lyle. His key relationships are built on mutual respect and a shared sense of duty, though he is not afraid to challenge others or speak his mind.

Nathan’s notable ability is pyrokinesis, the power to generate and control fire. He demonstrates an advanced level of control, shaping flames into elaborate forms and adjusting their intensity as needed. This makes him a formidable combatant, able to both neutralize threats and protect civilians with precision. His combat style blends performance with practicality, reflecting his larger-than-life persona. Additionally, his ownership of Helios Energy grants him financial independence and control over his own hero activities, reinforcing his commitment to autonomy and self-expression.