Prince Diamond, also known as Prince Demand (プリンス・デマンド Purinsu Demando, Prince Diamond in the English dub) and Prince Demande, is the leader of the Negamoon Family and the absolute ruler of the Negamoon. He was manipulated by Wiseman into attacking Crystal Tokyo and taking over the Earth. Finding Crystal Palace to be invincible, he sent one of his commanders, Rubeus, to the past to take over Tokyo by securing crystal points. However, Rubeus's plans were all foiled by Sailor Moon, and after his death, Diamond sent Emerald into the past to carry out her plan of taking over Tokyo by filling its vulnerable spots with dark energy. After several failed attempts, Diamond called her back.