The third Sorcerer General, a wizard who turned himself into a vampire before he joined the dark army. He sought the power to overthrow Arshes Nei and Kall-Su by drinking the blood of many virgins. In the anime, Yoko, who was sent to find the absent wizard, was captured by a werewolf working for Di-Amon; in the manga, the werewolf was killed by Dark Schneider as Lucien, prompting Di-Amon to step in and imprison Yoko, Larz, and Lucien. Sean Ari and Kai Harn were also captured, but this was a ruse that lead to a magical battle with Di-Amon. Unfortunately, Di-Amon was very nearly invincible, which lead to Kai being bitten, and Sean would have shared that ordeal, had Yoko not defended her. After a struggle against the seal and Lucien's will, Dark Schneider broke free on his own when Yoko was injured by Di-Amon, and proceeded to defeat the vampire with superior cunning (and egoism). Di-Amon was turned into dust by the light of dawn, then rose as a giant bat, which DS promptly placed under the Accused spell. In later issues of the manga, Di-Amon has reappeared, working his hardest to fight for Dark Schneider, whom he now calls his "beloved master". His nail remains bright blue.
Diamond's name is a reference to King Diamond. He is illustrated with King Diamond's typical face painting, and in the original Japanese OVA, he speaks imitating King Diamond's unique voice.