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Icon-decade.pngThis article is about a rider in Kamen Rider Decade.

For the original version, see Kohtaro Minami.
For the other A.R. World version, see Kohtaro Minami (A.R. World 2).

Kohtaro Minami (南 光太郎, Minami Kōtarō), alternatively spelt Kotaro Minami[1], is the original Kohtaro Minami's first incarnation from Kamen Rider Decade.


In an alternate reality where Kohtaro attained his powers as Kamen Rider Black RX without becoming the Century King Black Sun, he fights against the Crisis Empire, allied with Joe the Haze. Recently though, Dai-Shocker began invading his world, forcing Kohtaro to fight them as well. Even worse, an incident caused Joe to disappear, vanishing without a trace.

When Tsukasa Kadoya/Kamen Rider Decade and his allies came to RX's world, Shvarian initially mistook Tsukasa as Joe the Haze, ordering his grunts to kill him. Kohtaro then appeared to stop them, transforming into Black RX. Amidst his battle against Shvarian, Kohtaro was ambushed by two of Dai-Shocker's soldiers, being attacked by them. Tsukasa then transforms into Decade, defeating one of Dai-Shocker's soldiers; the other soldier and Shvarian retreating. Facing Tsukasa as Decade, Kohtaro prepares to battle, believing him to be a new threat.

Before Kohtaro could fight, Natsumi Hikari intervenes, convincing him that Tsukasa is not the Destroyer of Worlds that he heard about. Canceling his transformation, Kohtaro explains the situation towards Tsukasa's group, with Tsukasa sulking over his own predicament.

Despite Natsumi and Yuusuke's words, Tsukasa remains dejected, creating a rift between them. Kohtaro intervenes, suggesting that like how he is fighting to retrieve Joe the Haze back, Tsukasa is fighting for his friends' sakes as well. Dismissing Kohtaro's motives as nonsensical, Tsukasa walks away from them.

Later, Natsumi's life is endangered from saving Tsukasa, with Apollogeist (A.R.)'s Perfector needed to save her. Learning of the situation from Yuusuke, Kohtaro helps Tsukasa retrieve it, reaffirming his vow to fight for Joe the Haze. This time, Tsukasa accepts Kohtaro's words, having been reminded of how much his friends meant.

During the battle against both Dai-Shocker and the Crisis Empire's forces, Apollogeist (A.R.) escapes into another world, using the chaotic situation to his advantage. Swiftly, Kohtaro transforms into Bio-Rider Form and faces all other enemies on his own, allowing Tsukasa to chase after Apollogeist (A.R.).

Kohtaro (Black RX on left) and Kohtaro (Black on right)

With Tsukasa trapped into an alternate world and the Crisis Empire allying itself with Dai-Shocker, Apollogeist (A.R.) returns to Kohtaro's world, intent on completing its invasion. Apollogeist (A.R.) confronts Kohtaro, knowing him to be outnumbered. Suddenly though, Tsukasa appears before them, managing to return.

Apollogeist (A.R.) is unfazed by this predicament, believing the odds to still be in his favor; summoning several Kaijin to prove his point. Tsukasa rejects Apollogeist (A.R.)'s words, stating that Kohtaro has continued to fight against such odds, so as to retrieve his loved ones. Dismissing Kohtaro's efforts to be pointless. Apollogeist (A.R.) is infuriated when Tsukasa disagrees, the latter preaching the importance of camaraderie in defiance.

Once transforming into Decade, Tsukasa gains the Kamen Rider Black card, with Kaito as Diend taking it from him. Stating that Tsukasa cannot the card, Kaito uses its powers to summon the other Kohtaro (in person, and not as a manifestation). Nodding to each other, both Kohtaro transform into Rider form, allied with Tsukasa and Kaito.

The four Riders fight against Apollogeist (A.R.) and his allies, destroying several of their forces. Though Tsukasa acquires Apollogeist (A.R.)'s Perfector, Kaito steals it away from him and retreats. Worse, Yusuke arrives to tell Tsukasa of Natsumi's condition, much to the latter's shock. Kohtaro and his counterpart tell Tsukasa to leave the situation to them, allowing Tsukasa and Yusuke to return to Natsumi's hospital.

Facing Apollogeist (A.R.), Kohtaro challenges him to a duel, both sides agreeing to fight without help. Fiercely clashing against one another, Kohtaro proves himself the stronger combatant and deflects Apollogeist (A.R.)'s shield strike, stabbing him in the process. In desperation, Apollogeist (A.R.) summons the Rhinoceros Mutant to attack Kohtaro. Witnessing Apollogeist (A.R.) go against his word, the other Kohtaro assists his counterpart by destroying the Rhinoceros Mutant. The situation to their advantage, the two Riders use their Double Rider Kick on Apollogeist (A.R.), turning him back into his human form. Defeated, Apollogeist (A.R.) swears vengeance before escaping into an alternate world.

The battle won, Kohtaro oversees his counterpart return to his own world, before reuniting with Tsukasa. Having learnt of Joe the Haze's situation, Kohtaro calmly accepts it without issue. Surprised, Tsukasa questions whether Kohtaro is okay being alone. Kohtaro assures Tsukasa that he is not alone, as even when apart from one another, Joe the Haze will always be his friend, Glad to hear this, Tsukasa takes a photo of Kohtaro, with Kohtaro acknowledging Tsukasa to be his friend as well. Affirming Kohtaro's words, Tsukasa gives out a chuckle and bids farewell. Kohtaro nods in response, watching Tsukasa leave on his Rider Machine.

All Riders vs. Dai-Shocker

The original Kohtaro Minami in All Riders vs. Dai-Shocker, appearing identical to his World of Black RX counterpart.

In Kamen Rider Decade: All Riders vs. Dai-Shocker, just as most other A.R. World riders, this Kohtaro's existence is presumably ignored, and the original Kohtaro Minami appears - although in his movie appearance, the original Kohtaro was portrayed as identical to this version of the character.


Similar to his original counterpart, Kohtaro is an honorable man with a firm sense of loyalty. Since the disappearance of his friend, Kohtaro has made it his mission to locate Joe the Haze, vowing to fight all odds. Though initially hostile to Tsukasa's presence as Decade, Kohtaro quickly accepted him as a fellow Rider via Natsumi's words, encouraging Tsukasa to not take his friends for granted.

Fighting Style

Possessing three Rider forms, Kohtaro utilizes each accordingly, dependent on the foe faced. As Black RX, Kohtaro has sufficient strength and speed, with the Revolcane being his personal weapon. As Roborider, Kohtaro relies on power and endurance, alongside the Vortech Shooter for long-ranged battles. In Biorider form, Kohtaro gains access to great speed and agility, alongside liquid-based abilites and the Bioblade. Combined with his immense skill in combat, Kohtaro is shown to be a highly skilled fighter, suffering no defeats onscreen.

Evidently, Kohtaro is also a swift learner, overwhelming Shvarian in a rematch with RX form alone. Unlike their initial encounter, Kohtaro did not lose momentum when Dai-Shocker intervened in the battle, with Biorider winning against all four foes simultaneously.


Black RX

Kamen Rider Black RX

Rider Statistics:[2][3][4]

  • Rider Height: 198.8 cm
  • Rider Weight: 88 kg

Rider Senses:

  • Eyesight: 3 km[4]

Ability Parameters:

Black RX is a photosynthetic warrior as well as the evolved form of Black, using the sun as his main energy source.

Appearances: Decade Episodes 26-27.


RX Roborider

Rider Statistics:[3][4]

  • Rider Height: 198.8 cm
  • Rider Weight: 88 kg

Ability Parameters:

Roborider (ロボライダー, Robo Raidā) is a form where Black RX 's armor becomes bulky and more robotic-like, with black and yellow coloring and his Sunriser resembles a gearbox. During his duration as the "Prince of Sadness", both his strength and defense are enhanced. He is also unharmed by explosions or projectile weapons. The only downsides are that he moves slower than Black RX as well as possessing semi-robotic movement, slowing his reaction time.

This form is exclusive to Decade Episode 26


RX Biorider

Rider Statistics:[3][4]

  • Rider Height: 198.8 cm
  • Rider Weight: 88 kg

Ability Parameters:

  • Kicking Power: 140 t[6]
  • Maximum Jump Height: 72 m[3][4]

Biorider (バイオライダー, Baio Raidā) is a form where Black RX's armor becomes much sleeker, blue and silver all over and his Sunriser belt resembles a single Kingstone one. During his duration as the "Prince of Anger", his speed is enhanced. He can also transform with speed of up to 1000m into gel for escaping traps or attacking enemies while not getting hurt in the process, as he is near invincible while in his gel form. Out of it, however, RX sacrifices armor strength, leaving him more vulnerable to powerful attacks.

This form is exclusive to Decade Episode 26



  • Sunriser - Black RX's transformation device and an alternate form of the Vital Charger
  • Revolcane - Black RX's personal weapon
  • Wrist Communicator - Black RX's wrist-mounted communicator that he uses to summon his vehicles.
  • Vortech Shooter - Roborider's personal weapon
  • Bio Blade - Biorider's personal weapon


  • Acrobatter - The revived version of the Battle Hopper used by Black RX
    • Roboizer - An alternate form of the Acrobatter used by Roborider
    • Macjabber - An alternate form of the Acrobatter used by Biorider.
  • Ridoron - Black RX's personal car

Rider Card

KamenRide: Black RX

  • KamenRide: Black RX (カメンライドブラックアールエックス, Kamenraido Burakku Āru Ekkusu): A Rider Card containing the power of Kamen Rider Black RX.

Kamen Rider Diend first used the card in the World of Decade, summoning RX alongside Super-1 and Agito to fight Dr. Shinigami and the Dai-Shocker Soldiers in the 7-Eleven promotional campaign.


  • Alongside Sohji, Kohtaro Minami (A.R. World) is among the few A.R. primary Riders in Kamen Rider Decade to not require any emotional guidance by Tsukasa Kadoya/Kamen Rider Decade, instead being the one to remind Tsukasa of the importance of camaraderie and unity.
    • Interestingly, like Sohji and Daisuke Yamamoto (A.R. World), Kohtaro Minami (A.R. World) is also the only A.R. primary Rider to never be defeated in a fair battle, essentially proving more than capable of handling the Crisis Empire and Dai-Shocker's monsters alone.




  1. 3 times Black (150 t) according to one source[7]
  2. 315 km/h[3][4]
  3. 1.2 times RX[3]
  4. 1.2 times RX[3]
  5. 120 t according to one source[6]
  6. 40 maccording to one source[3]
Icon-decade.png Kamen Rider Decade
Kamen Riders
Primary: Tsukasa Kadoya - Daiki Kaito - Natsumi Hikari
A.R. Kamen Riders: Wataru Kurenai - Yusuke Onodera - Wataru - Shinji Tatsumi - Kazuma Kendate - Takumi Ogami - Shouichi Ashikawa - Momotaros - Ryotaro Nogami - Sohji - Asumu - Kohtaro Minami (Black RX) - Kohtaro Minami (Black) - X-Rider (A.R. World) - Daisuke Yamamoto - Kazuma Kenzaki - Joji Yuki - Yuriko Misaki
A.R. Evil Kamen Riders: Chinomanako - Mimihiko - Kuchihiko - Kamen Rider Abyss - Dark Kiva - Ryuga - Orga - Dark Kabuto - Alternative
Other A.R. World Riders: Ren Haguro - Scissors - Zolda - Femme - Verde - Tiger - Imperer - Odin - Raia - Gai - Sakuya Hishigata - Mutsuki Kuroba - Takahiro Furuya - Kotaro Nogami - Arata - Ibuki - Zanki - Todoroki - Akira - Junichi Kaito - Haruka Miwa - Shin Magaki - X - Ixa - Saga
Prime Universe Kamen Riders: Kotaro Nogami - Urataros - Kintaros - Ryutaros - Sieg
Drivers: (Neo) Decadriver - (Neo) Diendriver - Kiva-la
Transformation Gear: Rider Cards - K-Touch - Card Holder - Diend Belt
Weapons: Ride Booker - Final Form Rides - Kiva-la Saber
Vehicles: Machine Decader - Machine Diender
Hikari Studio
Natsumi Hikari - Kiva-la - Eijiro Hikari
Other Allies
Ai Yashiro - Kivat-bat the 3rd - Garulu - Basshaa - Dogga - Reiko Momoi - Ai - Mai - Mi - Yuri Tomoda - Toko Yashiro - Deneb - Teddy - Kohana - Naomi - Owner - Toki - Yu - Grandma - Mayu - Natsumi Hikari - Chinatsu - Hikoma KusakabeIcon-crosswiki.png - KurokoIcon-crosswiki.png - Kurando TaniIcon-crosswiki.png - ShinkengersIcon-crosswiki.png - Masahiko Okamura (A.R. World) - Ritsuko Okamura (A.R. World)
Dr. Shinigami - Jigoku Taishi - Apollogeist - Jyumenki Yum Cimil - Shadow Moon - Kingdark - General Jark - Bishum - Yuki - Shvarian - Televi Bae-Kun
Worlds of Black & Black RX: Scorpion Imagin - Seamoon Fangire - Mantis Fangire - Rhinoceros Mutant - Ox Orphnoch - Worm Orphnoch - Frilled Lizard Orphnoch - Brachypelma Worm Aurantium - Brachypelma Worm Viridis - Tarantes Worm Purpura
World of Decade: Siomaneking - Ganikoumoru - Doras - Garai - Me·Vagis·Ba - Xu·Mevio·Da - Me·Ginoga·De - Go·Gadol·Ba - Leiurus Acutia - Formica Regia - Formica Pedes - Sheerghosts - Raydragoons - Psycorogue - Butterfly Orphnoch - Giraffe Orphnoch - Longhorn Orphnoch - Slug Orphnoch - Wild Boar Orphnoch - Pelican Orphnoch - Stinkbug Orphnoch - Arch Orphnoch - Elephant Undead - Giraffa Undead - Darkroachi - Kappa - Bakeneko - Hitotsumi - Coleoptera Worm Aeneus - Coleoptera Worm Croceus - Coleoptera Worm Argentum - Geophilid Worm - Subst Worm - Cassis Worm Gladius - Albinoleo Imagin - Mole Imagin - Rat Fangire - Sungazer Fangire - Bat Fangire
World of Amazon: Go·Jalaji·Da - Propheta Cruentus - Camponotus Worm Maxilla - Bakeneko - Yobuko
Dai-Shocker Combatmen - Dai-Shocker Scientists - Destron Combatmen
Super Shocker
Narutaki - Wasp Woman - Neo Organism
Zanjioh - Jaguarman - Beaded Lizard Man - Hilchameleon - Xu·Goma·Gu - Go·Jalaji·Da - Volucris Falco - Solospider - Scorpion Orphnoch - Titan Undead - Kodama - Sectio Worm Acuere - Cobra Imagin - Gecko Imagin - Sungazer Fangire
Super Shocker Combatmen
World of Kuuga: Me·Garido·Gi - La·Doldo·Gu - Go·Babel·Da - Go·Bemiu·Gi - Me·Byran·Gi - Go·Jaaza·Gi - Me·Garima·Ba
World of Agito: Me·Vagis·Ba - Xu·Mevio·Da - Me·Ginoga·De
The Lords
Taurus Ballista
Formica Regia - Formica Pedes
Mirror Monsters
The Contract Monsters
World of Ryuki: Darkwing - Volcancer - Destwilder - Gigazelle - Abyssodon (Abysshammer - Abysslasher)
World of Negatives: Dragblacker
Wild Mirror Monsters
World of Ryuki: GuldThunder - Zebraskull Bronze - Megazelle - Negazelle - Omegazelle - Magazelle
World of Den-O: Gelnewt
World of Negatives: Raydragoons
Orphnochs / Lucky Clover
Momose - Shukawa - Genda - Shirogane
Butterfly Orphnoch
The Undead
World of Blade: Kamata - Hajime Shijo
Buffalo Undead - Elephant Undead - Capricorn Undead
World of Diend: Fourteen - Bossroach - Darkroachi
World of the Rider War: Deer Undead - Scarab Undead - Lizard Undead
魔化魍 Makamou
Gyuki - Bakegani
Kappa - Bakeneko - Ooari - Tengu - Ubume
Sou Otogiri
Coleoptera Worm Argentum - Geophilid Worm - Subst Worm
The Imagin
Alligator Imagin - New Mole Imagin
The Fangires
Beetle Fangire - Yuki
World of Kiva: Ryo Itoya - Swallowtail Fangire - Lion Fangire
World of the Rider War: Shark Fangire - Silkmoth Fangire - Horsefly Fangire - Warthog Fangire