Thousands of years ago, the evil emperor Talpa attempted to conquer the Earth. Defeated, he was banished to the Nether Realm and his armor was divided into 9 separate suits. Now, he has returned to conquer Earth, having reclaimed 4 of the suits. The other 5 are in the possesion of those who are the only hope of stopping him: The Ronin Warriors.

[Source: Anime News Network]

Although Talpa has been defeated, the Warriors don't get much of a break. As they celebrate Ryo's birthday party, the news tells them of a strange killer in samurai armor wreaking havoc in New York. And the armor looks very familiar. Now, they will have to battle the ancient sorcerer Shikaisen for Sage's life!

[Source: AniDB]

A strange, silent warrior appears. When the Inferno armor is summoned to battle him, the mysterious warrior calls forth his own armor—a black copy of the Inferno armor! Now, the warriors will find themselves half a world away fighting once more to save humanity, but this time, from their own armor!

[Source: AniDB]