The compilation film Ninjascope, drawn from episodes of the classic ninja/tokutsatsu mashup Kamen no ninja Aka-Kage (aka Masked Ninja Red Shadow) is available for free to Prime members on Amazons streaming site. It is dubbed rather than subbed, but it's not badly done. The story concerns three ninjas who fight against a cult run by magicians who can, on occasion, call up giant monsters. There's also a lot of different battles of magic between the cultists and the ninjas. It's a pretty wild, and campy, ride, but entertaining if you like the old school special effects used in Japan in the 60's.