Child of the Sun, Kamen Rider Black RX
Used by
Tengen Toppa Lazengann
Kamen Rider Kuuga (A.R. World), Kamen Rider Decade, Kamen Rider Black (A.R. World), Joe the Haze (A.R. World)
Crisis Empire, Decade (Violent Emotion), Dai-Shocker, Golgom
Human (Cyborg)
198cm (Normally), 100 meters (Size-shifted)
Kamen Riders
Kamen Riders

Kohtaro Minami (南 光太郎 Minami Kōtarō) is the original Kohtaro Minami's first incarnation from Kamen Rider Decade, and is both the resident Rider of the World of RX, and Kamen Rider Black RX.


He is a man who fights the Crisis Empire as Kamen Rider Black RX (仮面ライダーBLACK RX Kamen Raidā Burakku Āru Ekkusu), able to become either Robo Rider (ロボライダー Robo Raidā), or Bio Rider (バイオライダー Baio Raidā). However, with Dai-Shocker appearing in his world, he finds himself outmatched by the new monsters while searching for his friend Joe the Haze. Natsumi Hikari convinces him that Tsukasa Kadoya is not the Destroyer of Worlds that he heard about. Though he eventually learns of Joe's fate, Kohtaro is not saddened as his friend would be with him in spirit.


After becoming Kamen Rider Black RX, Kohtaro crossed paths with his future Rider machine, Acrobatter, whom he often talks with rather humorously. Also to be noted is that unlike in Black's World, Kohtaro seemingly managed to help Nobuhiko regain his former self as he died after saving some kids. The death of Nobuhiko seemed to have strengthened his will as he swore in his heart that he would defeat the Crisis Empire.


Black RX
  • Rider Height: 198cm
  • Rider Weight: 88kg
  • Ability Perimeters
    • Punching Power: 30 tons
    • Kicking Power: 45 tons
    • Max Jump Height: 60m
    • Maximum Running Speed: 100m/5s

Black RX is the current Kamen Rider form of Kohtaro Minami, a photosynthetic warrior, using the sun as his main energy source. His Sunriser has the two pieces of Kohtaro's shattered King Stone. His signature finishing move is the the RX Kick.

Robo Rider
  • Rider Height: 198cm
  • Rider Weight: 120kg
  • Ability Perimeters
    • Punching Power: 60 tons
    • Kicking Power: 30 tons
    • Max Jump Height: 25m
    • Maximum Running Speed: 100m/8s

Robo Rider 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. His weapon is the Vortech Shooter, an energy firing pistol.

Bio Rider
  • Rider Height: 198cm
  • Rider Weight: 85kg
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  • Ability Perimeters
    • Punching Power: 45 tons
    • Kicking Power: 75 tons
    • Maximum Jump Height: 90m
    • Maximum running speed: 100m/2s

Bio Rider is a form where Black RX's armor becomes much sleeker, blue and silver all over and his Sunriser belt resembles a single King Stone belt. During his duration as the "Prince of Anger", his speed is enhanced. He can also transform with the speed of up to 1000m into gel for escaping traps or attacking enemies while not getting hurt in the process, as he is invincible while in his gel form. Out of it, however, RX sacrifices armor strength, leaving him more vulnerable to powerful attacks.

Creation King RX

Kamen Rider Decade can use the RX Final Form Ride card to rebuild Kotaro's kingstone for a time, increasing his fighting capabilities greatly, and evolving him into the Creation King for a time.


  • Despite first meeting his Black counterpart in Decade's series, it is implied that the two have somehow met prior to the events of the series

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