Movie
Description
Kinniku Mantarou, protagonist of the sequel series to his father Suguru Kinniku's story, is the 59th prince of Planet Kinniku. Born to Suguru and Queen Bibimba in an era of prolonged peace, this privileged upbringing fostered a spoiled, lazy, and initially cowardly disposition, marked by a strong aversion to training or responsibility. He possesses blue eyes, pale skin, and stands at an average human height of 176 cm (5'9"), complemented by a muscular physique. His signature attire consists of a dark blue leotard featuring a yellow vertical stripe and light blue left side, adorned with a "KIN" chest emblem. He completes this look with dark brown gloves, yellow boots, a face mask allowing a tuft of brown hair to sprout, and a head fin characteristic of his planet's people.

Named after Ultraman Taro, Mantarou remained ignorant of his father's heroic legacy until encountering his advisor, Alexandria Meat, due to Suguru's annulled fight records. His personality reflects inherited traits, including early-fight hesitation from inherited cowardice and a lecherous streak leading to crushes on figures like Rinko Nikaido and Jacqueline Muscle. However, threats to friends or dishonorable actions by opponents awaken his capacity for growth, triggering the hereditary "Burning Inner Strength." This state manifests the Niku Mark (肉) on his forehead, dramatically amplifying his strength, stamina, and technique. His fighting style evolves from dependence on his father's Kinniku Buster and Kinniku Driver to original finishers like the Muscle Millennium and Muscle Gravity. Additional abilities include the Mantaro Air kick and the unconventional use of potent flatulence—fueled by his favorite galbi beef-and-rice bowls—for propulsion or distraction. His base Chojin Power registers at 930,000.

Key relationships shape his path. Meat provides foundational mentorship. His one-sided crush on Rinko Nikaido evolves into a mutual friendship offering emotional support. His attraction to Jacqueline Muscle develops alongside her growing respect for his bravery during the Chojin Olympics. A rivalry with Kevin Mask begins antagonistically, fueled by Kevin's disdain and alliance with villains like the d.M.p, but gradually shifts toward grudging respect and eventual alliance. His mentorship of Chaos Avenir forges a profound, trusting bond where Mantaro nurtures Chaos's confidence; Chaos's death becomes a pivotal motivator. His closest friendship, a Heterosexual Life-Partnership with Seiuchin, faces severe strain during the Ultimate Tag Tournament when Mantaro's dismissive insults drive Seiuchin to join the antagonistic Hell Expansions, requiring significant effort to reconcile.

His story arcs chart significant development. The Hercules Factory arc establishes his reluctant entry into heroism, culminating in defeating his aging father Suguru to graduate and earn the "Mask of Glory," though low grades assign him to protect a minor park. The d.M.p arc sees him defeat villains like Tel-Tel Boy and MAXman, displaying tactical ingenuity and beginning his acceptance of responsibility. At the Chojin Olympics, he reaches the finals only to lose decisively to Kevin Mask, triggering a Heroic BSoD and retreat; this defeat forces introspection and off-screen training, leading to improved conditioning and technique. The Demon Seed arc showcases his growth as he defeats General Devil to save allies. The Ultimate Tag Tournament arc confronts his leadership failures, particularly the alienation of Seiuchin, requiring him to rebuild trust and ultimately succeed with Chaos as his partner. Physical manifestations of his early struggles include accumulating unhealed injuries reflecting poor power control, later overcome through disciplined training.