Band of Ninja

Tales of the Ninja is a 1967 Japanese film directed by Nagisa Ōshima. It is based on Sanpei Shirato's manga Ninja Bugeichō. Rather than making an animated adaptation, Ōshima decided to simply shoot the panels of the manga in order, adding narration and employing zooming and panning techniques.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.