Kurogane has black fur, with dark markings on his face and body. He has dark patterns under his eyes and muzzle, but also small spots and stripes in his face, legs, back and tail.
Kurogane is sent to kill Yamabiko Kurohabaki together with Gekka and Shikkoku, but Orion, Heizō, and Tyson come to the site and drive them out. Later, Kurogane, Gekka, and Shikkoku collide with Rigel, Kotetsu, and the side-switched Masashige. Masashige kills the three assassins to protect his comrades.