シャドームーン
was born on the day of a solar eclipse alongside his stepbrother Kotaro Minami, revered by the Gorgom as the heirs to their leader's throne: the Century Kings "Shadow Moon" and "Black Sun". Raised together, the two were like brothers. Once the two were of the ideal age, Gorgom captured them and infused them each with a King Stone. While Kotaro manages to escape with his memory intact, Nobuhiko's mind was wiped clean while left in a state of suspended animation before being finally reborn as Shadow Moon through the Stones of Earth, Heaven, and Sea. Shadow Moon sets up his regime as a general of Gorgom, serving as Black's nemesis and forcing him to fight him so he can become the new Creation King. In their final battle, Shadow Moon is weakened by Kamen Rider Black after the Satan Sabre is used to slash his King Stone. Though he appears to die after being left inside the Gorgom headquarters when it explodes, Shadow Moon returns years later to seek revenge against Kotaro, who is now Black RX. However, he lost all of his memories related to Gorgom after its destruction. He is finally defeated by Black RX when he thrust the Revolcane through Shadow Moon's King Stone, destroying it once more. He turns back into Nobuhiko, renouncing his evil ways as he saved two children trapped in the explosive lava, shortly before he dies.