The Betrayal Arc is the eighth arc in the History's Strongest Disciple manga series</span>
The arc begins at the Ragnarok hideout, with Loki telling Valkyrie, Freya, Thor, and Berserker that he could’ve defeated Kenichi and Hermit if Odin hadn’t stopped him. But the real problem is that a new gang called Yomi has been running amok on their turf. Loki also told him that Odin was the only one that trained under Kensei in secret while the others never even met him. Thor ignored him, since he didn’t care about not having a master as long as he could spread his Combat Sumo all around the world. Freya was about to fight Thor if Valkyrie hadn’t reminded them that private fights between fists are forbidden. Before leaving, he secretly told Number 20 that he planted the seeds of his plan into action. At school, Kenichi was still thinking about what he finishing move was, but in battle he always forgets. Nijima told him that he used his finishing move against a fake Loki at the cafe they were at and named it Strongest Combo. Nijima told Kenichi about a pit club being run by Ragnarok’s seventh fist, Thor. Kenichi didn’t want to do it, but Nijima told him that if he doesn’t attack first then an event like Honoka’s kidnapping would happen again. Outside the Pit Club, Nijima devises a plan to have Kenichi fight Thor without having to fight anyone else first. Nijima had Takeda and Ukita stay outside to prevent them for being noticed, but they were noticed by the Shinpaku Alliance that was supposed to be left outside. Nijima used his brainwashing to have Thor fight Kenichi one-on-one. Kenichi wanted to make a bet first which was that if Kenichi wins then Thor must leave Ragnarok, but if Kenichi loses then Kenichi will do anything Thor wants. Thor remembered that Siegfried left Ragnarok to find himself. The match started in the ring before Thor told Kenichi that he must become Thor’s Sumo apprentice if Kenichi loses. Thor landed some powerful hits on Kenichi, but didn’t defeat him. Takeda saw that Thor has the advantage in the ring, since you can move a lot in a small ring. Kenichi used his Strongest Combo on Thor although the throw was difficult due to Thor’s weight. Eventually, Kenichi shifted Thor’s center of gravity and tossed him up and out of the ring making Kenichi the winner. Thor honored the deal and said he would quit Sumo, but Kenichi told him it was a bet to leave Ragnarok and he should keep improving his Combat Sumo. Before leaving, Nijima told Thor that Kenichi wasn’t a subordinate, he was his friend. Thor remembered his friendship with Siegfried and knew that's why he left. The Shinpaku Alliance carried Kenichi home for his victory against Thor.
Kenichi was being overconfidence when Nijima told Kenichi about about his and defeating over half of Ragnarok. This overconfidence had Kenichi slack off on his training though. Kenichi decided to fight his masters, but he was easily beaten and was heacily injured when Apachi kicked him through the wall and fence. Kenichi was hospitalize in the dojo, but Hayato told him that he improved by suriving Apachi's kick
At Ragnarok hideout, Thor was receiving punishment by the other fists (except for Odin) For leaving Ragnarok. But Valkyrie only used on ekick on Thor, which had Freya thinking Valkyrie will betray Ragnarok as well with some hearing from Loki. On the way to Ryozanpaku, Kenichi and Miu was Valkyrie who they thought was kicking a kitten in a box, but was actually was her feeling it. Valkyire tried to lie fearing that Nijima would spread news all over school, but Kenichi and Miu won't tell it. However, Freya's team thought that Kisasa was teaming up with the enemy. Kisara couldn't couldn't keep the kitten at her house so she wanted Kenichi or Miu to take him, But Honoka is allergic to cats and the Master of Ryozanpaku seem scary. At Ryozanpaku, Miu was worried about the kitten, so she went to help the kitten. The master tortured Kenichi to have tell why Miu is acting so strange. Kenichi went to tell Miu that the Master will allow Miu to keep the kitten at the dojo, but ran into Kisara. On the street, Kisara tried to get the kitten adopted by someone, but scares them away with her eye's. Kisara. Miu went to get an umbrella to keep the kitten dry, but Freya's Valkyrues showed up to punish Kisara for her betrayal. Kisara couldn't fight them, since she had to protect the kitten. Luckly, Miu returned with Kenichi to help her when they saw Kisara in trouble. Miu took the kitten to the vet to make sure it was okay while Kenichi had to face the Valkries. Unfortunately, Kenichi couldn't fight them due to his No-Hitting-Girls policy. Thing got worse when left to be finished off by the Valkries. But Kenichi get back up and escaped with Kisara. Tochumaru was around and launched a red flare in the sky to signal Shigure for help. At the vet, Miu was told that kitten just fainted and the the veterinarian will find someone to adopt him. Back on the street's, The Valkyries finally surrounded Kenichi and Kisara, but Shigure showed up to save them. Kenichi warned them to get away, fearing that Shigure would kill them, but they though he was lying. Kisara wanted Shigure to leave, but the former was knocked out by the latter. Kenichi had Shifure to just a wooden spoon made by Akisame to fight them and surprisingly broke the Valkrie's weapons and cut thire clothes forcing them to retreat. Kisara the left to for back to Ragnarok. At Ragnarok's hideout, Kisara kicked down telling Freya that she doesn't want to use weapons and that she's officially quitting Ragnarok. Loki's doppelgangers surrounded her, but Kisara kicke to of them and esaped throuh a window. At school, Kenichi remembered that Ryoanpaku is willing to take in the kitten, but the kitten at the vet already adopted by a family.
- A group called YOMI was mentioned that would be trouble for Ragnarok and Shinpaku Alliance.
- Loki was planning on taking over Ragnarok.
- Thor and Valkyrie quit Ragnarok.
- Freya leads a team called Valkyries that consist only of women that uses weapons.
|Relations Arc||Betrayal Arc|| Apachai Flashback Arc (Manga)|
Final Clash Arc (anime)
|97 | 98 | 99 | 100 | 101 | 102 | 103 | 104 | 105|
|37 | 38 | 39|