Lemme guess. Duh ninjas really be duh black man, not no Chinese muthaf—kas.
No, just more folklore and myth and historical national pride and marketing than actual truth. The “Ninja” really weren’t a thing until early novelists and folklore made it a “thing”. Kind of like how we hear the emperor was worshipped during WWII. Both are part fairytale and very, very, very complicated to explain in all the involved complications that come with the long history and various ancient regional, cultural, and ideological embellishments from long before Japan was what we know as “Japan”. It’s all just become folklore now due to thousands of years of “stuff”.