The story follows Jotaro, a wandering ninja who becomes entangled in a deadly conflict between rival clans after a brutal massacre wipes out his comrades. As he investigates, he discovers that the violence is tied to a sinister conspiracy involving a demonic sect seeking power through forbidden rituals. This group employs grotesque, otherworldly abilities – blurring the line between human and monster – to eliminate their enemies and dominate the region.

Jotaro joins forces with a mysterious female survivor whose own past is steeped in tragedy and vengeance. Together, they confront increasingly bizarre and terrifying foes, each wielding unnatural powers. As the battles escalate, Jotaro must rely not only on his physical skill but also on inner resolve to resist corruption and defeat the dark forces threatening to consume the land.

Known for its stylised violence, eerie atmosphere, and imaginative (often shocking) supernatural elements, NINJA WARS is a standout entry in early 1980s Japanese genre cinema.