|This article is about a rider in 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.).
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
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.
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.
- Rider Height: 198.8 cm
- Rider Weight: 88 kg
- Eyesight: 3 km
- Punching Power: 70 t
- Lifting Power: 1 t
- Kicking Power: 120 t[note 1]
- Maximum Jump Height: 60 m
- Maximum Running Speed: Approx. 100 m per 1.1 seconds[note 2]
Black RX is a photosynthetic warrior as well as the evolved form of Black, using the sun as his main energy source.
- Rider Height: 198.8 cm
- Rider Weight: 88 kg
- Punching Power: 84 t[note 3]
- Kicking Power: 144 t[note 4][note 5]
- Maximum Jump Height: 48 m[note 6]
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.
- Rider Height: 198.8 cm
- Rider Weight: 88 kg
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.
- 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
- 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.
- 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.
- Kamen Rider Decade
- Hobby Japan. (2005). S.I.C. Official Diorama Story: S.I.C. Hero Saga. Vol. 1. p. 59-61. ISBN 978-4894253896.
- Takeshobo. (2001). Masked Rider Chronicles: A History of Cyborg Soldier's Battle. p. 170, 186-189. ISBN 978-4812407837.
- Kamen Rider Official Data/Perfect File.
- Kamen Rider Battle: Ganbarizing card: G3-051.
- Futabasha. (2013). General Facts of Kamen Rider: Turbulent Fierce Battle Chapter. p. 82. ISBN 978-4575306040.
- Kamen Rider Battle: Ganbarizing card: K1-052.