Shinjirō Hayata is the son of Shin Hayata, the original human host of the legendary Ultraman. He inherited the "Ultraman Factor" from his father, granting him innate superhuman strength, durability, and agility. This manifested in childhood, such as surviving a multi-story fall at age five with minor injuries. Initially, Shinjirō viewed his abilities as a curse, isolating him from normal life and causing accidents like unintentionally breaking a bully's leg. Secrecy surrounding their powers strained his relationship with his father. A confrontation with the alien Bemular revealed his father's past as Ultraman. Shinjirō joined the Science Special Search-Party (SSSP) and received powered armor modeled after Ultraman. This suit harnesses his Ultraman Factor, featuring retractable forearm Specium Blades for close combat and the ability to fire the Specium Ray energy beam by crossing his arms. A chest "Limiter" regulates power; releasing it temporarily amplifies his abilities, causing the suit to glow red. He later spontaneously developed flight during a battle with Black King to protect civilians. Shinjirō possesses a strong sense of justice and empathy, prioritizing protecting innocent lives over lethal force. He often spares defeated enemies if they pose no further threat, a stance that clashes with teammate Dan Moroboshi, who views this mercy as naive. Despite his willingness to fight, Shinjirō despises killing and experiences profound guilt and rage when bystanders are harmed, like SSSP agent Igaru's death. This idealism sometimes causes self-doubt about his effectiveness as Ultraman, worsened when adversaries frame him for destruction, drawing public scrutiny. Psychological trials significantly shape his evolution. He grappled with the revelation that the Star Cluster Council manipulated Earth's peace treaties with aliens and endured his father's murder by Mephisto, a Council agent. Public distrust intensified when Mephisto falsely implicated him in terrorism, leading Shinjirō to question his role. During isolation, he reflected on his responsibilities and accepted that being Ultraman is defined by compassion and resilience, not just power. This culminated in a battle against Edo—the disguised Alien Zetton and Council chairman—where humanity's renewed faith empowered him to victory. He ultimately embraced his identity, recognizing his humanity and values make him worthy of the Ultraman legacy. Key relationships shape his journey: his protective father, Shin Hayata, initially shielded him from the SSSP; SSSP scientist Mitsuhiro Ide mentors him and provides technological support; childhood acquaintance Rena Sayama challenges his views after blaming Ultraman for her mother's death during a past battle, though their bond deepens into mutual affection; Dan Moroboshi serves as a foil, criticizing Shinjirō's methods while grudgingly acknowledging his growth.