Members of the Black Moon Clan come from the planet Nemesis, a world thought to be the 10th planet of the Solar System. It is described as a planet of "negative energy", having the ability to vanish from sight, but remained traceable by X-Rays. All members of the Black Moon Clan have black, upside-down crescents on their foreheads (the inverse of the marking of the Silver Millennium). They wear earrings which, according to the Materials Collection, are made of Black Evil Crystal and allow them to teleport.
All members of the Black Moon Clan were defeated with Rubeus fallen and dead while the Negamoon Sisters reformed, and Prince Diamond and his two minions Emerald and Sapphire defeated, leading up to a final confrontation with the Black Moon Clan's last member Wiseman who revealed himself to be the Death Phantom.