Prince Demande

Prince Demande, better known as Prince Diamond is the leader of the Black Moon Clan and the older brother of Saphir.

Appearance
He has short white hair and wears a white suit with gloves and a blue cape. The suit has blue designs embroidered in it, has a diamond as the clasp and he wears the black crystal earrings.

Pretty Soldier Sailor Moon (original timeline)
Prince Demande resented Crystal Tokyo, believing them to be corrupt and that their lifespans were profane. Wiseman approached him and convinced him to use the power of the Malefic Black Crystal, Demande planned to use the power of the crystal to time travel and create a new history before the reign of the Moon Kingdom. When the Black Moon Clan attacked Crystal Tokyo, the first time Neo-Queen Serenity went to find her daughter, Chibiusa. Prince Demande then became obsessed with the Queen and kidnapped Sailor Moon upon realising was the same person. Demande kisses her and is promptly pushed away. Usagi tries to transform but came to realize the dark energy of the planet had absorbed her powers. However, she managed to escape with her friends and caused the palace to collapse. After losing Sailor Moon, Prince Demande realizes he was simply being used by Wiseman and revolted against him. In the process, Demande was forced to kill his brother and used the Silver Crystal he got from Sailor Moon and another from the future Black Lady to destroy the space-time continuum. His plan was stopped by Sailor Pluto. As he attempted to kill Sailor Moon, she and Tuxedo Mask destroyed him using the Cutie Moon Rod.

Pretty Soldier Sailor Stellar
Prince Demande makes his first appearance in Act 2 along with the rest of the Black Moon Clan. He decides reluctantly to let Hikari live and to become one of the members of the Black Moon, though he is still suspicious of her being a spy. His reasoning is that he can keep an eye on her this way, and to keep her around because he finds her attractive (though he won't admit this to himself).

He is then shown in Act 3 interacting with Wiseman, who is pressuring him to obtain the Legendary Silver Crystal and Chibiusa Tsukino. Demande frustratingly assures his advisor that these tasks will be accomplished. After Wiseman becomes alerted that they're being watched, Hikari reveals that she was watching them. Wiseman questions who she is and where she came from, with Demande informing him that Hikari is a Sailor Senshi. Wiseman urges him to keep an eye on Hikari, sensing she could become a nuisance to his plans.

In Act 4, Demande calls on his younger brother Saphir in an attempt to get some information regarding Hikari. Saphir responds that, according to what Hikari told Koan, she's from "the real world" and questions why he hasn't disposed of her already if he's worried about her turning out to be a spy. After he fails to answer, Saphir begins to goad him about becoming fond of Hikari. Demande is quick to deny this, reaffirming his obsession with Neo-Queen Serenity and claiming that he wants Hikari around for her valuable powers. Saphir eventually accepts this reason, though still privately holding his suspicions.

Trivia

 * Demande often makes appearances in vanderlindemorgan's other works, whether his role is major or just being a cameo. These roles include Sailor Moon: Parallel Side Stories and The Revival of the Once Great fanfiction series.
 * Depending on the translator, his name can be translated as "Demando", "Demand", "Diamond" or even "Diamonde".
 * Unlike the other members of the Black Moon, Demande's name origin cannot be traced back to any specific language.