Kendo Rappa is a very large, muscular man with long light-colored hair. His face is hidden beneath the plague mask given to him by the Shie Hassaikai. He dons a tattered t-shirt and dark pants covered by a light tunic and decorated with two belts. Rappa also sports his signature gloves, which cover his hands with several leather straps and his knuckles with metal.
Kendo Rappa is a very hot-blooded man who thrives on violence and bloodshed. He has a warrior-like mentality and all he cares about is seeking out a battle that can satisfy him. Rappa believes it's unbecoming for a fighter to use weapons and that everyone should fight with the power of their bodies. 
Unlike most of the Eight Expendables, Rappa only serves Overhaul because he hopes to one day defeat him. Rappa's entire mindset revolves around provoking others into a fight to the death where he can stake his life on the line. If someone cannot satisfy that interest, Rappa wants nothing to do with them. If someone can give him the thrill he seeks, Rappa shows them great respect.
To a certain degree, Rappa appears to have his own sense of honor. He would rather fight alone and win with his own strength than fight alongside Tengai. Rappa also allowed Fat Gum to take Eijiro to heal so they can fight again sometime. 
Kendo Rappa used to spend his days fighting in an underground fighting ring. In that fight club, fighters could go berserk with their Quirks. Rappa's battle prowess made him too powerful for all his opponents and he never got the deathmatch he always desired.
At some point, Overhaul attends a fight to recruit Rappa to the Yakuza. Rappa tried to kill him and ended up "dead" himself, or so he thought. Overhaul used his Quirk to repair Rappa's body.
Rappa joined the Shie Hassaikai with the sole intent of fighting Overhaul. He has been killed all five times he's challenged Overhaul. 
During the raid of Chisaki's hideout, Kendo is paired with Hekiji Tengai. When Irinaka launches Fat Gum and Eijiro Kirishima into another room, Hekiji and Kendo are already waiting for them. Launching a barrage of punches, Kendo manages to break through Eijiro's Red Riot Unbreakable. Taishiro tries to punch Kendo, but Hekiji protects his partner with a barrier.
Kendo complains when Hekiji stops him from attacking Taishiro, to which Hekiji reminds him that Overhaul paired the two up because their Quirks have great synergy. Kendo replies by trying to attack Hekiji, which he blocks with his Quirk. A confused Hekiji asks Kendo what he is doing, to which Kendo replies that he does not care about Overhaul's plans and that he only wants to kill. Hekiji decides to let him do as he pleases, while also reminding him to address Overhaul properly.
As Taishiro prepares to fight back, Kendo orders Hekiji not to interfere, to which Hekiji assures him that he will not. Upon seeing Eijiro's fear, Hekiji notes that he has already given up and expresses pity for the young hero. After Kendo is done assaulting Taishiro, Hekiji notices that Taishiro is preparing for another counterattack and tells Kendo to finish things quickly. As Kendo tries to finish Taishiro off, Eijiro interferes, taking his attacks and attempting his own counterattack; however, Hekiji blocks it with a barrier. Hekiji simply notes how meaningless it was for Eijiro to take these attacks.
Soon, however, he realizes that Eijiro's actions were not in vain as Taishiro emerges from the dust and releases all the impact he stored from Kendo's punches with a single powerful blow. Hekiji however creates a barrier with maximum defense that absorbs most of the impact, which prevents the two from being knocked out. Kendo stands up again and claims that it is a fight to the death and he is not dead yet. He asks Taishiro to take Eijiro to the next room with first-aid supplies. Hekiji questions the selfish attitude of Kendo and demands that he follow his orders, but Kendo knocks out Hekiji by stomping on his chest and declares that he wants a fight to the death against Eijiro.
After treating Eijiro's injuries, Taishiro asks about Chisaki's plan and the reason Kendo is following him, so Kendo tells him that he is only around to defeat Chisaki someday and that Chisaki wants to reinstate the yakuza.
Immense Strength: Kendo has great strength as his fists were powerful enough to break through Eijiro's Red Riot Unbreakable technique and injure Taishiro, both of whom are known for excelling at defense. He uses this in conjunction with brass-knuckle style gloves.
Strongarm (強肩 Kyōken?): Kendo's Quirk allows him to rotate his shoulder sockets at extreme speed and power, giving him commensurately fast and strong punches. Kendo uses these to release an intense prolonged flurry of punches. It is noted that this Quirk cannot be used for longer than a few seconds before needing to stop, leaving an opening.
Unlike the other seen members, Kendo does not seem to fully respect Chisaki. This is shown when he openly declares his dislike for his partnering with Hekiji based on their Quirks, and the reasoning behind it, preferring to fight on his own rather than rely on the "Spear and shield" plan they were given. He also does not refer to Overhaul correctly, instead calling him "Overhole", although this could imply a more forgetful or ignorant nature rather than disrespect.
Outside of these facts, Kendo appears to care very little for Chisaki's goals or ambitions, openly revealing them to Taishiro, seemingly unconcerned with the repercussions for committing such an act.
Kendo does not appear to particularly like Hekiji, though works with him out of necessity. Clashing with his calm and calculative nature, Kendo dislikes Hekiji for attempting to restrain him when it comes to battling. He will even go as far as to attack Hekiji when he will prevent him from getting a fight that he desires, or even when he tries to stop Kendo from displaying his own brand of honor.
- Kendo's last name means thug or villain (乱波 Rappa?). His first name contains the kanji for shoulder (肩 kata?) and movement (動 dō?).
- With his bloodthirsty nature and violent Quirk, Kendo seems to represent a corrupted version of the first tenet of the actual eight precepts of Buddhism: do not kill other living things.
- ↑ My Hero Academia Manga: Chapter 142.
- ↑ 2.0 2.1 My Hero Academia Manga: Chapter 146.
- ↑ My Hero Academia Manga: Chapter 142.
- ↑ My Hero Academia Manga: Chapter 143.
- ↑ My Hero Academia Manga: Chapter 145.
- ↑ My Hero Academia Manga: Chapter 146.