Ninja Scroll is a classic and then some. It's one of the most highly-regarded anime movies ever made for a reason, setting a high bar that's never quite been topped, even by shows like Samurai Champloo.
The story is about a ronin, Jubei Kipogami, who becomes embroiled in a plot by a shadowy figure called "The Shogun of the Dark," who is planning to overthrow the Tokogawa Shogunate government.
The Shogun of the Dark's secret weapon is a group of superhuman operatives called the Eight Devils of Kimon. Eight ninjas with their own bizarre abilities, from living tattoos to a hive of wasps built into their bodies.
The leader of the Eight Devils is Himoru Gemma, a man who Jubei has a past with. A man whose special power is that he CANNOT be killed!
Jubei is recruited to eliminate the devils after he is poisoned by Dakuwon, a rascally government spy sent to investigate the Shogun of the Dark's machinations after an entire village is mysteriously wiped out by a "plague." The old man says Jubei will get the cure after the job is done. The two are later joined by Kagero, a female ninja whose clan leader assigns her the job of investigating the Shogun after her clan is all but decimated by one of the Eight Devils.
This series is everything westerners have wanted from eastern storytelling, but rarely gotten. It's sophisticated, well rooted in real events, eastern mysticism and political intrigue which in Japan means cultural intrigue. The heroes are relentless and smart, the bad guys are ingenious and fascinating. Everybody in this movie has a trick up their sleeves, and it's great to watch.
The sexuality is pretty frank. There's a rape scene; a Devil who keeps a snake hidden...uhm, let's not go there; Gemma himself is bi-sexual and it is revealed that he's had sex with at least two of his seven devils. But like the graphic violence it serves the story and creates a believable and awesome world where anything can happen.
The writers use Japan's history as ammunition to drive the narrative forward and it's culture as a tool to draw the viewer in. You may have seen a lot of sword flicks, but not one like this. It is uniquely Japanese and wholly original. Forget about King Arthur or ancient Rome or Greece. Feudal Japan is where the great stories are at!
The animation is among the best hand-drawn stuff to come out of Japan, and the way this world is depicted is lush and engrossing. If you haven't seen Ninja Scroll, then see it. It receives my highest possible recommendation.