Legend of the Shadowy Ninja: The Ninja Dragon [空想科学任侠伝 極道忍者ドス竜]

The secretive realm of the world's deadliest ninja warriors is thrown into chaos as one by one, ninja clan leaders are brutally assassinated! What fiendish foe has the power to kill the most dangerous men in the world? To avenge their dead leader, three ninjas must face this hidden enemy. They'll need all their stealth and ninja trickery to survive!