The Ainu portrayed in the film are an indigenous people who primarily live in Hokkaido, the northernmost Japanese island. Up until the late 19th century, both Ainu and Hokkaido were referred to as Ezo.
Kamui Nupuri means "mountain of the gods" in the Ainu tongue.
Hiroyuki Sanada, is better known for his various live-action roles. This film was the first and only time he worked on an animated film.
Tenkai:
Jiro! Struggle more! Despair more! After your scolding, show me a good counterattack!
Jiro:
In heaven and earth, you are all I can rely on. Whether going along with you will bring about misfortune or hope for now I do not know. But there is no going back now!
Oyuki:
Why did you save me? Why? Why didn't you kill me?
Jiro:
Why did YOU save me?
Andô Shouzan:
We are all born naked, and die naked. In the meantime, all we do is work, east, shit, and sleep.
Andô Shouzan:
I am Andô Shouzan. As you can see, I'm a hardheaded old fart.
Andô Shouzan:
Missed out on dying, did you? I doubt that one would go out of his way to be resurrected in a place like this, but as long as you've been saved, just give up and recuperate. Get that noxious viciousness out of your system and wake up to your hunger, why don't you.
Oyuki:
Do you... want to kill me? As soon as the Lord Tenkai catches up with us, I'll probably go back to being a mere Shinobi, and take your life. Now, do whatever you want to me.
Iga Chief:
Tenkai! Having him as a pupil the one thing I regret in my entire life!
Jiro:
Sam!
Sam:
Yes, Master!
Jiro:
Stop calling me "Master".
Sam:
Yes, Master!
[Jiro is framed for the murder of his mother, Oyaruru as the screen is dominated by phantasmogorphic imgery.]
Chorus:
Murderer! Parent-killer! You shall be cursed! To hell with you, mother-killer! Murderer!
Factual errors: Mark Twain was the pen-name of Samuel Clemens. In the movie, however, he meets Jiro and identifies himself as Mark Twain. Samuel Clemens never referred to himself by his pen-name in real life.
Continuity: During his first fight with Hanzou, Jiro sustains a wound on the left side of his midsection. As he is resting at a hot spring area, he is tending to the right side of his midsection.