With Rei now dead, only three of the Six Sacred Fists of Nanto remain and Kenshiro sets off to find the remaining ones. One of them, a man named Souther, has proclaimed himself to the "Holy Emperor" and seeks to conquer the world as well.

Kenshiro meets a blind martial artist rebelling against Souther named Shu, who is also one of the Six Sacred Fists.

While saving a group of children slaves from Souther's troops, Ken remembers that he once fought Shu in the past, back when he was still a child.

When a young member of Shu's resistance is killed, Ken must protect the fallen rebel's fiancee from Garzus, one of Souther's men.

Ken finally comes face to face with Souther. However, the Holy Emperor stands immune to Ken's Hokuto Shinken techniques.

Defeated by Souther, Ken is captured so he could be used as a sacrifice for the completion of Souther's Holy Cross Mausoleum. However, Shu's young son Shiva sets off to infiltrate Souther's lair and save Ken, even at the cost of his own life.

Ken is rescued, but at the tragic cost of Shiva's life. However, with Ken still injured from his fight with Souther, Shu decides to hide him and challenges Souther for the sake of his people.

Shu is defeated by Souther and is forced to carry the stone that will serve as the summit of Souther's pyramid. Sensing Shu's struggle, Ken awakens and quickly regains his full strength.

Ken arrives at the Holy Cross Mausoleum and witnesses Shu's public execution at the hands of Souther. But before dying, Shu miraculously recovers his eyesight and sees the now grown Kenshiro before dying. Toki and Raoh also arrive at the scene to witness Ken's fight with Southeer.

Before accepting Kenshiro's challenge, Souther recites his tragic childhood and his motive for building the Holy Cross Mausoleum. Ken fights Souther again and struggles, until he finally fathoms the secret behind Souther's invulnerability.

With Ken aware of his weakness, Souther uses the ultimate technique of his Nanto Hō-ōken style as a last resort. The stage is set for the final round.

Raoh regains his full strength and seeks Koryu, Ryuken's former rival, to test his power, while Toki, who was once willing to settle using his skills to heal the weak, has regained his determination as a martial artist.

Raoh challenges Koryu to battle to gauge his strength. Toki learns of Raoh's recovery and is determined to stop him at any cost.

Toki and Raoh's past is revealed as the two are reunited at the place where they were adopted by Ryuken.

Determined to fulfill the childhood promise he made to his brother, Toki fights Raoh to a death match.

Ken meets Ryuga, a martial artist and servant of Raoh whose astrological sign is a solitary star that is neither, part of Hokuto and Nanto.

Ryuga, who swore royalty to Raoh and his tyranny, witnesses Kenshiro's compassion to others and is determined to find out which of the two brothers is more to fit to lead the world.

Ryuga challenges Kenshiro to test his strength, but Ken is unwilling to fight back.

Determined to challenge Ken, Ryuga decides to lure Ken to his lair by kidnapping and wounding Toki.

Ken sets foot into Ryuga's lair, determined to save Toki and finish his battle with Ryuga once and for all.

Ken reflects on the life of his ally Rei, the man who sacrificed his life to save Ken.

Ken remembers Rei's battle against his rival Yuda, the man who once tormented Rei's beloved Mamiya.

Ken remembers Shu, a selfless man whose encounter with a young Kenshiro led him to his destiny.

Ken remembers Souther, the strongest of the Nanto Seiken masters.