Malefic Black Crystal

Featured in Pretty Soldier Sailor Moon R, this enormous black gem swells in strength the more hostility surrounds it. It originates on Nemesis, where Death Phantom seizes on it to threaten the Earth, and the Black Moon Clan schemes to let it swell until it can pry open the Black Gate and doom the world. Every clan member apart from Saphir sports earrings cut from the same crystal. It should not be mistaken for the separate Black Crystal.

Across the 90s anime, the crystal sits deep within Nemesis, its malice amplified by a reactor at the planet's core. Wiseman keeps a large round shard that he turns against the paired Silver Crystals of Sailor Moon, appearing as Neo Queen Serenity, and Chibiusa, and the gem also works as the key that unseals the Dark Gate. Black Lady tries to pull all of its darkness into herself to destroy the planet. The struggle ends when Sailor Moon and Chibiusa join the might of the present and future Silver Crystals through Moon Crystal Power, drowning it in light and undoing it for good after the last clash with Wiseman.

In the manga, the very center of Nemesis seems to be formed from this crystal, and the Black Moon Clan siphons its power to carry out their plans to rewrite history. It later comes out that Wiseman has merged with the whole of the planet itself. The Crystal adaptation keeps the gem in much the same role, with Wiseman boasting that it matched even the Silver Crystal and held the power to rule over everything.

Wiseman, also known as Death Phantom, is the crystal's master. As a stone of concentrated evil, it commands the element of darkness outright, capable of firing off crushing waves of malignant energy that leave ruin and rot behind, and it can even smother the Silver Crystal's abilities, as it does while Usagi is held captive on Nemesis. Localizations gave it many names, from the DiC dub's "Dark Crystal" and the Tokyopop "Black Poison Crystal" to the Kodansha "Malefic Black Crystal," the Kanzenban "Beguiling Black Crystal," and the ADV DVDs' "Evil Black Crystal."