The Fist of the North Star manga series features a large cast of characters created by author Buronson and illustrator Tetsuo Hara. Set on a post-apocalyptic Earth after a nuclear war, the story follows a warrior named Kenshiro, the successor of a deadly martial art known as Hokuto Shinken, which gives him the ability to kill his opponents by striking their secret vital points, often resulting in an exceptionally violent and gory death. Kenshiro travels the wasteland fighting various gangs, bandits, and warlords who threaten the lives of the defenseless and innocent. Many of the characters are fighters trained in various forms of martial arts with skills that reach superhuman levels.

Hokuto Shinken is an ancient martial art rooted in different fighting styles dating back 1,800 years ago from China. Its founder was Kenshiro's and Hyoh's ancestor Shuken of the ancient "Hokuto Sōke" ruling line, who combined Keiraku Hikō with his . This martial art makes use of the opponents' 708 Meridian Channel Hidden Points, also known as simply Hikō, tsubo or pressure points). These pressure points destroy the enemy from within. The Hikō can also be used to heal and even to revive the dead. While a normal fighter uses 30% of his natural abilities, a Hokuto Shinken successor knows how to utilize his remaining 70% using . A Hokuto Shinken successor can also resist attacks on the pressure points with the , copy techniques after witnessing them only once with , move with lightning speed using a leaping technique which leaves indentations on the ground and use , an expert user can often radiate Tōki from his own body as an aura (Tōki no Aura, or Fighting Spirit Aura) whilst focusing it for attacks. It can be used to launch ki-based attacks that can be used to strike targets, even tiny ones, like the Keiraku Hiko with at long range, or, to defend the user from attack. Use , a secret technique of Hokuto Shinken that allows the user to move in a pattern resembling the Hokuto Shichi Sei (Big Dipper). This technique allows the user to attack their opponent from seven blind spots inherent in a human's field of vision, with each blind spot corresponding to a star in the Big Dipper constellation of seven stars. Hokuto Shin Ken follows the tradition: it can only be passed down from one father to one son, and there can only be one successor at a time. Sons that do not succeed in becoming successor must never practice the art again, or risk having their memories erased or fists destroyed.

The two ultimate Hokuto Shin Ken techniques are , a technique where the user becomes one with the Void. This technique can only be performed by one who completely understands sadness. The second ultimate technique is , this technique allows the user to create a pocket Dimension devoid of anything (Heaven and Earth are erased). In this world of void, everything aside from the two fighters' fists is nullified, and the loser is completely erased from Existence.

"Hokuto Shin Ken" is named after the asterism Hokuto Shichi Sei, which is the Japanese name as the Big Dipper.

Kenshiro

The protagonist of the series, Kenshiro is the youngest of the four Hokuto brothers and the chosen successor of Hokuto Shinken.

Raoh

The eldest of the four Hokuto brothers, Raoh is a conqueror who takes the mantle of Kenoh or 'The King of Fists', and later gains the additional title of 'The Conqueror of the Century's End'. Believed to be the strongest and obvious choice to become the sole user of Hokuto Shinken, Raoh is a towering and intimidating man standing at least 7 feet tall (in some fights he is depicted being substantially larger i.e. 10–12 feet). After learning of Kenshiro's chosen succession as the single user of Hokuto Shinken, Raoh abandons his loyalty to his brothers and his master to wander the wastelands and become the ruler of all including conquering Heaven itself. Before leaving however, his master Ryuken begs him to give up his ambitions of conquest by never practicing his martial art or to "seal his hands" (achieved by destroying/removing his hands or his mind or by committing suicide). Raoh of course refuses and kills his master in a duel as Ryuken's fading health stops him from defending himself. Before dying Ryuken tells Raoh that because of his prideful ambitions he will never be able to achieve true mastery of their martial art, which infuriated him and planted seeds of doubt into his mind. Raoh would go on to become one of the most powerful warlords of the wastelands and eventually lead armed forces larger than the Southern Cross 6, the likes of Shin or even its leader Souther (Thouser). Raoh is a true power house of destructive force, as his technique is the "Hard Fist" style of Hokuto Shinken. This style focuses on crushing blows and straightforward assaults along with energy waves that destroy most anything they are directed at. Raoh's most notable character trait both in and out of combat is his overwhelming need to always press further and never retreat, not even one step or else his pride and claim of being the greatest will be in question.

Toki is the second of the four Hokuto brothers. He is a pacifist who seeks to use Hokuto Shinken as a healing art. Toki's self-made technique, , is an art that is capable of healing or destroying that which it is used on, with its damaging techniques inflicting minimal pain in spite of their destructive nature. When fatally wounded with this style, the victim experiences feelings of euphoria and compassion, instead of horrific pain. Toki is from the Land of Shura, and along with Raoh, was orphaned and adopted by Ryuken, who is seeking a student to train. Although he originally doesn't train Toki, Toki showed incredible potential, and promises that he will stop Raoh if he falls down the wrong path. Toki and Kenshiro soon became friends, with Toki personally training Kenshiro in some techniques of Hokuto Shinken, sustaining a distinctive scar on his back from when he protected a young Kenshiro from a falling tree. He sustained severe Radiation sickness while protecting Kenshiro, Yuria and a large group of children. His illness precluded him from becoming the Hokuto Shinken successor and remained with him for the rest of his life.

Toki was voiced by Takaya Hashi in the TV series, Hideyuki Tanaka in Shin Hokuto no Ken, Kenyū Horiuchi in the Shin Kyūseishu Densetsu movies and Fitness Boxing: Fist of the North Star, and by Hiroki Touchi in the Ten no Haō anime series. Kirk Thornton voiced Toki in English dub of the TV series.

Jagi is the third of the four Hokuto brothers. Deceptive and evil, Jagi stops at nothing to win and frequently cheats during battle. He never really mastered Hokuto Shinken, relying on his sawed-off shotgun to finish off most of his opponents. After a botched attempt at killing Kenshiro, he is left with a hideously disfigured head as a reminder of his failure. Consequently, he hides his head by wearing an iron helmet and a section of plating over the disfigured portion of his face to control the constant pain it produces. Harboring a severe hatred for Kenshiro, Jagi was the one who manipulated Shin into betraying Kenshiro. Afterwards, he engraves seven scars on his chest in the same Big Dipper-like pattern as the ones on Ken's chest and began terrorizing numerous villagers with his gang, while claiming to be the true Kenshiro himself. Kenshiro tracks him down and easily defeats him, despite Jagi having somehow learned basic Nanto Seiken as well as Hokuto Shinken. His face finally starts exploding but as he dies he reveals that Toki and Raoh are still alive and gleefully declares his hopes that Kenshiro would be destroyed in the battles to come.

Jagi was voiced by Kōji Totani in the TV series, Chikao Ōtsuka in the 1986 movie, David Itō in the 2007 OVA Legend of Yuria, and Yasuhiko Kawazu in Fitness Boxing: Fist of the North Star. In English dubs, he was voiced by Dan Woren in the 1986 movie and Peter Lurie in the TV series. Chris Penn portrayed Jagi (renamed "Jackal" in this adaptation, unrelated to the other character with the same name) in the 1995 live-action movie.

Ryuken The previous successor to the Hokuto Shinken style. was the sifu who adopted and trained Raoh, Toki, Jagi, and Kenshiro in the Hokuto Shinken style. After he chose Kenshiro as his successor, he was slain by Raoh, a feat made possible by chance; he suffered a stroke at the moment he was about to seal Raoh's fist. Kenshiro did not know the real cause of Ryuken's death, having been told that Ryuken died from illness, until Toki revealed the shameful secret during their first battle. Both Kenshiro and Raoh reflect on Ryuken's teachings during difficult situations. In Fist of the Blue Sky, his real name is revealed to be Ramon Kasumi, younger half-brother of Yan Wang, Kenshiro Kasumi.

In the original TV series, Ryuken was originally voiced by Junji Chiba, later replaced by Ryūji Saikachi in the later episodes and 1986 movie, with Kōji Totani as the younger version of him. He was also played by Chikao Ōtsuka in the Shin Kyūseishu Densetsu series, by Mugihito and Takashi Kondo (as a young boy) in the Fist of the Blue Sky anime series, and by Atsushi Ono in the Ten no Haoh anime series. Malcolm McDowell played Ryuken in the 1995 live-action movie.

Kohryu is a former rival of Ryuken who competed against him for the succession of the Hokuto Shinken. During the duel, both Kohryu and Ryuken realize that their strength and skills are equal, and that both of them could be killed in the fight. Acknowledging that, Kohryu decided to give up the successorship to Ryuken, and to begin living an ascetic peaceful life in the mountains. Raoh, after healing himself of the wound given to him by Kenshiro, challenges Kohryu to test his body and defeats him. Raoh, however, spares the lives of Kohryu's two sons, Zeus and Aus.

Nanto Seiken is an assassination art that is characterized as the polar opposite to the Hokuto Shinken style. Whereas Hokuto Shinken destroys enemies from within through the use of the keiraku hikō vital points, Nanto Seiken teaches its practitioners to kill with sheer force through the use of stabbing and slicing techniques, with additional styles utilising elements such as air currents to cut opponents from a distance. The Nanto Seiken school has branched out to 108 sects, with the six top masters of these sects being known as the , whose fates are intertwined to a star within the Nanto constellation. With the exception of the Last General of Nanto, who uses no martial art, each Nanto master is trained in a style of Nanto Seiken named after a bird.

Shin is Kenshiro's first major adversary in the series. Shin represents the and is the successor of the style. Originally Shin was Kenshiro's acquaintance, who secretly desired Kenshiro's fiancée Yuria from afar, but knew Yuria's heart was for Kenshiro and gave up pursuing her. However, his mind was eventually corrupted by Jagi. Shin challenged Kenshiro, after destroying Ryuken's grave stone, and defeated him, engraving the seven scars on his chest afterwards and subsequently taking off with Yuria by force. He then forms the King organization and builds Yuria the city of Southern Cross. However, he is unable to win Yuria's love and after her suicide attempt, Shin entrusts her to the Nanto Goshasei for her protection. Sometime afterwards, he is challenged by Kenshiro in his lair and is defeated. Mortally wounded, he claimed that Yuria had died from the fall, then he jumped off the roof of his own palace so that the fatal impact would kill him, instead of Kenshiro's attack.

Shin was voiced by Toshio Furukawa in the TV series and 1986 movie and by Takuya Kirimoto in the 2007 OVA Legend of Yuria and Fitness Boxing: Fist of the North Star. In English dubs, he was voiced by Michael McConnohie in the 1986 movie and by Steven Blum in the TV series. Costas Mandylor played Lord Shin in the 1995 live-action movie.

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