The story focuses on Kenichi Shirahama, an average 16-year-old high school student who has been picked on his whole life. However, on his first day of class, he meets and befriends the mysterious transfer student, Miu Fūrinji. Driven by his desire to become stronger, he follows her to Ryōzanpaku, a dojo housing several masters of diverse martial arts, led by her grandfather Hayato Fūrinji, who is known as the strongest man on Earth. After learning basics from Miu, Kenichi is able to beat a high-ranking member of the school's karate club, and becomes a target for all the delinquents in the school.
The gang leaves with Honoka to a special summer spot.
Niijima puts his master plan to create his personal legion in motion.
Instead of waiting for another attack from Ragnarok, Kenichi decides to take the initiative and confront Thor, another member of the Eight Fists, after he hears about his location from Niijima.
Thor gets punished by the rest of the Eight Fists League after he chooses to leave the gang. Kisara's unwillingness to join in the punishment makes the others suspicious of her allegiance. Later, Kenichi and Miu spots Kisara taking care of an abandoned kitten, and decides to help her find a home for the kitten. Seeing that Kisara has made contact with Kenichi and Miu, Freya's personal guards attack her for her supposed betrayal.
Eager to have a rematch with Miu, Kisara and her crew set for the school, but Kenichi discover her intentions and decides to stand in her way to protect the play.
Kenichi discovers that Tanimoto is in fact Hermit, the 6th fist of Ragnarok, and must fight for his life against him.
Natsu Tanimoto, the president of the drama club, invites Miu to perform "Romeo and Juliet" together at the school's play, to the despair of Kenichi.
Even after rescuing Honoka and breaking his ties with Ragnarok, Tanimoto is determined to finish his fight with Kenichi.
Hoping to win Kenichi's affection, Izumi seeks for Nijima's aid and ends up paying a visit to Ryouzanpaku.
Loki kidnaps Honoka and attracts Kenichi to an old church, where he meets Hermit, and their fight begins.
While Miu takes the kitten to a vet, Kenichi tries to protect Kisara from the Valkyries unit, but his oath to not hit women puts him at a serious disadvantage against them, until Shigure comes to his aid.
While trying to recall his memories involving his ying-yang badge, Kenichi ends up meeting Odin, the supreme leader of Ragnarok, and their past connection is revealed
Kenichi and Miu aid Takeda and Ukita against Kirara's army.
Kensei Ma sneaks out or Ryouzanpaku to solve a family problem of his, but is followed by Kenichi, who ends up meeting his daughter Renka.
Kenichi fails to convince his childhood friend to reconsider and must face his amazing power. Meanwhile, Niijima tries to recruit Tanimoto to the Shinpaku Alliance using a trump card of his.
During his fight with Kenichi, Hermit's tragic past is revealed.
All of Kenichi's attacks seem to have no affect on Shinnosuke. Even though Kenichi is stronger, his opponent has more fighting experience so he is still at a disadvantage. Miu is not allowed to come to his aid because it would hurt Kenichi's pride. Kenichi becomes careless and is knocked to the ground and is about to be torn apart, Takeda comes and punches Shinnosuke to one side and escapes carrying Kenichi back to the Ryouzanpaku dojo. To Kenichi's dismay his masters all criticise him for being defeated, because it means it will lead to further defeats. Niijima continues to spread his manipulated version of the news throughout the whole school. After his defeat has been revealed to everyone, he is constantly chased around by school delinquents. All of the masters at the dojo decide that Kenichi should be taken in as a true disciple of Ryozanpaku, meaning he should stay there and must live only for martial arts.
Kenichi trains with the Elder himself in order to surpass Ryuto's technique by training in the center of Japan called Yamagata which Kenichi has to survive in for 7 days and 7 nights but, can he survive? And Niijima tries to recruit Kisara by using her love for cats.
Siegfried appears in the last moment to protect Niijima from Berserker. Meanwhile, Miu deals with the Valkyrie unit by herself as Kisara has an one on one match with Freya.
Berserker has been defeated by Hermit, so Kenichi challenges Odin to a second fight. Ryoto accepts the challenge and the long awaited battle begins. Kenichi makes full use of the training he had received from Furinji-sama. Kensei eagerly watches the fight between First Fist Odin and Kenichi from a distance.
Ragnarok's Loki and Siegfried capture Niijima and Kenichi goes for his rescue along Miu.
Kenichi finds himself in dificulties against Seigfried, until he starts to put into practice all of the fruits of his training.
The attacks on Kenichi are now becoming a daily occurrence and one day his opponent ends up pulling out a knife against him. Because it was his first time against a weapon, Kenichi freezes up, forcing Miu to save him. Now Shigure-sensei, the weapon specialist, has now decided to teach Kenichi the basic art weaponry.
Cornered by Kenichi's unexpected reaction, Ryuto utilizes a dangerous technique to rise up his power beyond his body's limits, and the reason for his grudge on him is revealed. As their fight comes close to a conclusion, Kenichi continues determined to win, not only for his own sake, but for his childhood friend's too.Watch Now:Amazon
Kenichi and Hermit's fight is interrupted by Loki, who using Honoka as a hostage, renders Kenichi unable to fight back, much to Hermit's anger.