服部正成
A.k.a. Hattori-kun, is the protagonist of the series, a little ninja named after Hattori Hanzō, because he was a descendant of Hattori Hanzō himself. He is 11 years old and 40 kg and is 140 centimeters tall. He is the boy who usually contests Kemumaki when he performs mischief. Hattori's main weakness is that he is terrified of frogs (Ranidaphobia) ; this often leads him into trouble when a frog is visible. He wears blue coloured ninja robes, with a red belt. He always explains what a good ninja does and what others should also do. His powers can be compared to a master ninja. He also has a strange habit of saying ~"degozaru" or "nin nin" ("ding ding") after almost every sentence. His girlfriend seems to be Tsubame.