Following the conclusion of the large-scale coalition campaign, the entirety of China is in a state of economic recovery. The victor of the battle, the state of Qin, is no different. There, the political parties led by Ying Zheng and Buwei Lü continue their inner conflict. Having played the role of king in the coalition battle, Zheng has the trust of the people—but Lü is far from out of the fight. In 18 months, he plans to interrupt Zheng's coming-of-age ceremony. Meanwhile, a Zhao army numbering 20,000 troops has set out toward Qin. In the royal court, due to the lack of generals capable of responding to the incoming threat, Lü slyly suggests that Zheng take command. However, Cheng Jiao, Zheng's half-brother, volunteers instead. As they grew to trust each other during the coalition battle, Zheng now accepts Jiao as his replacement. However, the Zhao forces retreat a mere half-day after clashing with Jiao's army. With trouble quickly brewing in the shadows, the internal struggle of Qin is only complicated further. There are only two men Zheng feels he can rely on: Bi, a general who commands 30,000 men; and Xin, the leader of the Fei Xin force.

Kinnikuman has proven himself worthy to be crowned the next king of Planet Kinniku. But at the ceremony, five other Kinnikuman's arrive, all claiming to be the true prince of Planet Kinniku. Now, a Royal Survivor Tournament is being held to decide the true successor to the throne, and with the help and support of his friends and with his recently acquired knowledge of the Ultimate Technique (The Muscle Spark), Kinnikuman fights for what is rightfully his.

Kinnikuman II Sei takes place several years after the events of the original Kinnikuman. Mantarou Kinniku is the 59th prince of Planet Kinniku and son of the renowned wrestler, King Suguru. Lazy, immature, and cowardly, Mantarou seems to have little in common with his heroic father. When a powerful group calling themselves the dMP threatens the Earth, only someone as powerful as Kinnikuman stands a chance against them. Not knowing the current whereabouts of the King, a plan is formed to have his son Mantarou take up the mantle. The idea of fighting super villains does not sit well with Mantarou, who initially runs away from his duty. He flees to Earth where he encounters Meat, his father’s old trainer. Despite Mantarou's shortcomings, Meat sees King Suguru in him, and believes he can set the prince on the right path. Thus begins Mantarou's journey to better himself and save the world.

Long ago, the king of Orvelia, Kyle, defeated the demon king Angmund and brought peace to the world. However, one hundred years later, demons have been sighted in the forests, threatening humanity once more. A scouting expedition is sent to verify the claim but only one member returns. Meanwhile, Riheet, the leader of a dark elf mercenary group, plots to take over Orvelia to exact revenge against the humans who forsook their race a century ago. The knight apprentice Kasel, accompanied by the priestess Frey, sets out to rescue Clause, an old friend who went missing in the tragic mission. However, along the way, Kasel discovers that he is the son of the revered King Kyle and the only one who can wield the Holy Sword Aea—the same sword that slew the demon king. To fulfill this destiny, the young knight must embark on a perilous quest, unseal the sword, and end the fear instilled by demons. As Kasel's journey to bring hope to humanity and Riheet's vow for vengeance intertwine, what fate could possibly await them?