Eleven-year-old Iga ninja Kanzo Hattori, steeped in the legacy of ancestor Hattori Hanzō, measures 140 cm tall and weighs 40 kg. He lives in Tokyo with the Mitsuba family—foster brother Kenichi and Kenichi’s parents, whose strictness he respects—while maintaining ties to his biological parents, Jinchu and Mrs. Hattori, and younger brother Shinzo, a trainee ninja whose admiration clashes with their differing views on discipline. Rigidly principled and naturally authoritative, Kanzo enforces high standards, driven by a protective sense of duty. Beneath his disciplined exterior lurk childhood bedwetting memories, a lingering fear of amphibians and reptiles, and impulsive decisions that betray his calculated persona. His unspoken fondness for kunoichi classmate Tsubame surfaces through their frequent arguments.

Tasked with mentoring Kenichi, Kanzo repeatedly thwarts rival Koga ninja Kemumaki’s schemes, their antagonism occasionally yielding to cooperation that hints at mutual respect. He employs classic ninjutsu like Hypnotism, Wall Walking, Smokescreens, and Wind Transfer, augmented by inventive tactics such as the Flying Squirrel Technique—gliding via duvet. His steel sword and shurikens contrast with Shinzo’s wooden practice tools.

Consistent across his 1981–1987 anime debut, 2012 reboot, and crossovers with *Perman* and *Doraemon*, Kanzo’s core identity adapts without compromise. A live-action film ages him into adulthood, diverging from main continuity. His arc emphasizes loyalty to the Mitsubas, reconciling rivalries, and confronting vulnerabilities, from admitting fears to navigating tensions with Tsubame. Relationships define him: exasperation with lazy ninja dog Shishimaru, patient guidance of resistant Kenichi, and clashes with Kemumaki that blend rivalry with grudging teamwork, all anchored by unwavering dedication to ninja ethics.