Nin x Nin: The Ninja Star Hattori(2004)

Nin x Nin: The Ninja Star Hattori is an action comedy following Kanzo Hattori, an apprentice ninja sent to Edo for his final training. His destiny takes an unexpected turn when his assigned master turns out to be Kenichi, a shy nine-year-old boy with no ninja skills whatsoever. As Hattori pledges to protect the reluctant child while upholding the ancient ninja code, he must also uncover why the rival Koga clan is thriving while his own Iga ninja village faces extinction. Meanwhile, mysterious attacks plague Edo—victims found unconscious with no visible wounds, each bearing the Koga crest. Kenichi, inspired by Hattori's determination, begins to find courage of his own, especially around Midori, a girl he secretly admires. Together, master and protector must navigate danger, duty, and unexpected friendship in a tale blending martial arts thrills with heartfelt comedy.