Animekagero Naruto Shippuden Blood Prison Movie 5 Ro Sub Exclusive -

The "Blood Prison" movie is technically a standalone (filler) film because it doesn't fit perfectly into the main series timeline (Naruto knows Killer Bee but hasn't mastered his Nine-Tails Chakra Shroud yet). However, the location itself is —Hōzuki Castle and its warden are mentioned in the Kakashi Hiden light novel.