Nobuhiko Akizuki, known as Shadowmoon, is a major antagonist in the tokusatsu series Kamen Rider Black. He is the foster brother of the protagonist, Kotaro Minami, and was transformed into the fearsome Shadowmoon by the cult Gorgom. As Shadowmoon, he serves as the century king and rival to Kamen Rider Black, creating an emotional conflict due to their brotherly bond. His tragic fate and complex relationship with Kotaro make him one of the most memorable villains in the franchise.