Influences from Japanese mythology are frequent throughout "Naruto," extending even to characters limited to single anime episodes, like the Legendary Stupid Brothers in Episode 142. Individually they're Raijin and Fujin, which are the names of two iconic Japanese deities with command over lightning and wind respectively.
Another major influence on "Naruto" is a fictional ninja named Sarutobi Sasuke. Author Masashi Kishimoto is clearly attempting to draw attention to this, given that he named significant characters both Sasuke Uchiha and Hiruzen Sarutobi. Furthermore, stories about Sarutobi Sasuke pit him against ninjas from a rival clan, perhaps inspiring in a broad sense the conflicts between ninja clans throughout "Naruto."
While Sarutobi Sasuke is something of a composite of real-world individuals — he's a koga ninja, which is a group that actually once existed — "Naruto" directly nods to real-life history too through Danzo Shimura and Dan Kato. Both of these characters share a name with a historic ninja named Kato Danzo who became renowned in Japan for his supposed ability to perform otherworldly feats.
So, even if the series is largely Kishimoto's original work, the fingerprints of various folkloric and historical figures, plenty familiar to a sizable portion of its Japanese audience, are all over "Naruto."
