This takes place in a post-apocalyptic world, full of ruin and chaos. As Raoh encounters a biker gang down an empty road, he easily kills its leader, Jirai, and slaughters most of the other gang members. Raoh meets up with Reina and Souga, who are requested by Goram the Demon King to perform in front of him. However, this was a plan for the three to overthrow this king. Raoh defeats Goram in battle and takes over the castle and its army as the "King of Fist".
Raoh has his army rebuild the castle within three days and trains them in combat. He sends his army to fight against the soldiers led by Gion the Wise King to take over the kingdom as a means for transportation. However, as Raoh's invasionary force enters into the nearby valley, they end up being trampled to death by a herd of wild horses, said to be ruled by a stallion deemed the Black King. Raoh, Reina, and Souga go to this valley themselves, where they witness the Black King protecting a dying foal against two wild tigers. The Black King and its herd agree to fight alongside Raoh and his army after they both kill off each tiger. After Gion realizes what happened, he surrenders his kingdom to them.
A mysterious woman named Sakuya offers to assist Raoh and company take down the impregnable kingdom ruled by Gaoh. Sakuya allows herself to enter the fortress in an attempt to seduce Gaoh, lying about her identity and her acquaintance with Raoh. She has him chase her around his bedroom at night, turning off the lights as they circle around. When Gaoh turns back on one of the lights to see Sakuya again, Reina shoots him in the head from the outside with a crossbow from the outside. As Raoh's army begins to infiltrate Gaoh's fortress, Reina fights Habaki, Gaoh's subordinate. Raoh catapults himself onto the fortress and kills Habaki as dawn approaches. Sakuya joins Raoh's army to serve as the tactician of the group.
Gion, now the warden, tells the group that a captive named Uighur has survived five executions, asking Raoh to settle the matter. However, Raoh releases Uighur from imprisonment and assigns him as the new warden. Raoh, Reina, and Souga travel into the abandoned city of Cassandra and meet an old man. He warns them of the various death traps inside the indomitable castle ruled by Amon the Dragon Emperor. After they easily pass through the obstacles, Amon confronts Raoh, but the latter repels the attacks. As a last resort, Amon activates a switch, causing the castle to start collapsing. During this time, Raoh tells Amon that even his own son was killed by one of the traps inside the castle, showing him a medallion the old man, revealed as his younger brother, had kept since the incident. Raoh, Reina, and Souga struggle to evacuate before the castle falls, while Amon is left alone to die under the rubble.
The group wants to recruit Toki, who runs a clinic in a poor village and heals the sick using acupressure, and he just so happens to be Raoh's brother. Reina goes to see Toki personally to convince him to join with Raoh, but Sakuya shows opposition to this, saying that having them together will end up in conflict. After Toki refuses to join, Raoh and Souga arrive with the army. Raoh orders his army to arrest Toki after the latter refuses to battle against the former to prove his strength as a martial artist. Uighur tries to express his duty as warden, using his whip to attack Toki. However, he dodges the whip and disables Uighur from attacking. When Sakuya visits Toki in his cell, she apologizes because she wants to protect Raoh from potentially being injured by Toki if the two brothers were to fight each other.
Raoh is told by Souga to go see Ryuroh, a former military strategist now living a peaceful life at a barren wind farm, in an attempt to recruit him in the army. Ryuroh tells Raoh that he is happy with his new life in the empty forest, though he recalls of how he led his troops, now broken up, to several victories in the past. Ryuroh tries to convince Raoh to change his ways and use his power to bring peace and not to cause warfare. Raoh sees this as an act of defiance and mortally wounds him, but realizes that Ryuroh was dying from an illness after their fight.
On his way back, Raoh comes across a man named Ryuga, who promptly engages in a fistfight against him, though Raoh withholds the final blow when he sees that Ryuga had no intention of defeating him. After having witnessed Raoh battling Ryuroh recently, Ryuga, believing that the only way to achieve order in the world is through force, decides to serve Raoh for his cause. Later on, it is reported that two armies are invading the fortress with a pincer attack. Raoh assigns Souga to go with Ryuga and fight off the army ruled by Igor the Lion King. After Ryuga kills the army general, the army surrenders, but he precedes to slaughter them while they bow down in fear. Souga tells Ryuga to stop, but this only creates tension between the two warriors.
Souga and Ryuga reconcile their differences and now they have to face Igor themselves. They behead this ruthless lion king and return to the fortress, bringing back his skull made into a wineglass to celebrate their victory. A mysterious martial artist known as King, who has taken over the city of Southern Cross, is said to be preparing to invade the fortress. Raoh sends Reina with Ryuga to investigate upon the matter. Reina and Ryuga reluctantly find a man named Juza of the Clouds, Ryuga's half-brother, in a local bar near the city. He reveals that their sister, Yuria, Raoh's childhood friend, committed suicide after she learned that King had destroyed neighboring villages to buy her love. When Ryuga tells a grieved Raoh about this, he decides to leave it alone for the sake of rule.
Raoh's army take down the army led by Jadum the Iron Emperor, while Reina to investigate the UD Gang hideout in the south. She is ambushed and then captured by Dagale, aide to the leader of the gang. As it seems that Jadum's army is lessening in numbers, Jadum transforms his body into steel and fights Ryuga and Sakuya head on, but he is shortly defeated afterwards. While imprisoned, Reina sees Isabella, a female assassin who served Dagale, being tortured to death after having received a scar on her neck from her last mission. Reina manages to free Isabella and herself and attempt to escape the hideout, but Isabella is momentarily shot with an arrow to her back. Raoh unexpectedly arrives to rescue Reina and confronts Juda, the leader of the gang, but Raoh decides not to kill Juda and continues on his way.
Souga and a group of men travel across a desert to a village posing as merchants, as to inspect if an army ruled by Pluto has passed by there. Souga gathers the villagers to interrogate how the flag of Pluto's army ended up in the streets. All of a sudden, a mysterious voice impales Souga in the chest by the now hypnotized villagers, saying that he will now have two months to live. Souga is forced to leave and inform Raoh about this. Raoh and the others go to the village themselves and attack Pluto's army. While there, Ryuga is also struck in the chest by the unknown voice. Raoh looks around and sees that a man named Gaiya was responsible for this, as well as for the fact that he has Pluto's army under his spell. Raoh defeats Gaiya in one blow, causing the army to retreat.
Sakuya is seen in the presence of Thouzer the Holy Emperor, but she chooses not to work under him anymore. Sakuya, accused of betraying Raoh, is sent to prison under suspicion, though she claims she serves Raoh out of love. As Raoh's army begin their raid toward Thouzer's castle, Raoh encounters Hucker and Lirong but easily kills them. Raoh later holds a meeting with Thouzer, who agrees to back down and let Raoh take the title of the "holy emperor" if he chooses to do so. It is revealed that Sakuya plans to take down the fortress on her own.
Reina is left to defend the office until Raoh and Souga return. Juda makes an appearance and begins to fight the warriors present in the office. Sakuya is released from prison as is to assist Reina in warding off Juda's army. Sakuya explains to Reina that she never betrayed Raoh, instead she merely predicted what would happen if Raoh went to see Thouzer in the first place. Juda has his army tear down the walls and attack the warriors within the fortress. Raoh manages to make it back to his kingdom and overwhelms Juda with his fists. However, Juda still has a trick up his sleeve, shooting Raoh with a giant howitzer. Fortunately, Raoh is able to destroy the large bullet.
Thouzer breaks his alliance with Raoh and challenges him to a duel. Both suffer grave injuries from their fearsome attacks, but they still continue to fight. Juda tries to attack Raoh from behind, but luckily Souga and Ryuga catches him. Raoh and Souther go at each other at full force, neither of them giving up. As they both makes the final blow, Sakuya stands in their way and takes both of their hits. As she is dying, she determines that both are unworthy of being ruler because of Souther's lack of love and Raoh's lack of sadness. After she passes away, Thouzer tells Raoh that he will follow Raoh without betrayal this time, but he will fight again if Raoh shows any sign of weakness during his ruling. Later on, Souga report to Raoh and Reina that someone broke into the prison, killing Uighur in battle and releasing Toki from