Hanagata is a pivotal figure in the narrative, first appearing as the enigmatic former president of the powerful Smart Brain corporation. He had disappeared several years before the main events of the story, leaving his position vacant and his motives a mystery. In the very first episode, it is revealed that he broke into a Smart Brain laboratory and stole three pieces of advanced technology known as Rider Gears, setting the entire conflict of the series into motion.

Hanagata is a deeply complex individual driven by a grand, and ultimately tragic, vision. As an Orphnoch himself, he was initially committed to representing the interests of his own kind. However, his research led him to a devastating conclusion: the Orphnoch are an incomplete life form. The process of evolving from a human causes their genetic structure to break down, resulting in a significantly shortened lifespan. The only being capable of rectifying this fatal flaw and completing the Orphnoch as the ultimate life form is a special entity known as the Ark or King Orphnoch. To find this king, Hanagata established the Ryusei School, an orphanage that served as a front to gather and observe children who had died and been resurrected as Orphnochs.

A fundamental shift in Hanagata's beliefs occurred when he witnessed many of these newly awakened Orphnochs become corrupted by their power, losing their human hearts and committing evil acts. This disillusionment caused him to change his goal from securing the future of the Orphnoch to finding a way to destroy them. He concluded that the Orphnoch, as a species, did not deserve to survive. In a direct act of sabotage against his former company, he stole the Rider Gears and entrusted them to his students at the Ryusei School, hoping they would use the power to fight against Smart Brain's genocidal agenda. He also worked in secret, developing the Riotrooper belts in a hidden underground facility at the school, though the development process was brutal and the failed prototypes often resulted in the death of the test subjects.

Hanagata's role in the story is that of a hidden orchestrator and a source of critical aid. He operates from the shadows, intervening at key moments to provide assistance or guidance. His power as the Goat Orphnoch is immense. He possesses extraordinary combat abilities, including incredible speed, strength, and martial arts skill. He is shown to be capable of single-handedly subduing the Dragon Orphnoch, who is considered one of the strongest and most feared of his kind, suffering no damage in the process. The Goat Orphnoch form is characterized by features resembling a mountain goat, including temporal horns, and stands 207 centimeters tall.

His key relationships are primarily with the Ryusei School students, whom he raised. He is their foster father, and they regard him with a mixture of respect, loyalty, and, upon learning the truth about his machinations, a sense of betrayal. He has a particularly significant relationship with Yuji Kiba, a kind-hearted Orphnoch who struggles to side with humanity. In his final days, Hanagata returns to Smart Brain, ousts the acting president, and appoints Kiba as the new head of the company, believing Kiba shares his own desire to protect humans. He also has a crucial interaction with Masato Kusaka, a user of the Kaixa Gear. Hanagata saves Kusaka's life and warns him repeatedly that continuing to transform is dangerous and will lead to his death. In the end, Hanagata’s own body reaches its limit due to his Orphnoch nature. Before he can reach his surrogate daughters to explain everything, his body disintegrates, leaving behind only sand. His final act is to implore Kusaka to survive, a wish that goes unfulfilled. Throughout his journey, Hanagata embodies the central conflicts of the story, a being who tried to play god with evolution, was consumed by his own ideals, and ultimately sought redemption by arming the very humans his kind sought to destroy.