|Occupation:||Leader of the Dark Sirius faction, pro wrestler|
|Associates:||Dark Maya, Dark Sumer, Dark Rachel, Dark Shem, Dark Ham, Dark Shard, Dark Japheth, Dark Monolith, Dark Dogon|
|Aliases:||Black Sirius Scorpion|
|First Appearance:||10th Anniversary Festival - Ai no Sanctuary|
Dark Nibiru was the leader of a group from the third planet of the Orion system, Dark Sirius, who came to Earth in search of the Silver Crystal. They believed that it had been stolen from them in ages past, and sought to make it a sun to illuminate their dark planet.
Dark Nibiru disguised himself as the wrestler Black Sirius Scorpion and, using dirty tricks, defeated Sensational Jaguar Mask. He then forced his defeated opponent to start attacking audience members in order to attract the attention of the Sailor Senshi, and then attempted to force Sailor Moon to give up the Crystal to him.
With the help of Prince Demande the Senshi were able to defeat his minions, and finally Sailor Moon and Sailor Chibi Moon together used Starlight Honeymoon Double Therapy Kiss to destroy him.
- In Babylonian mythology, the celestial body known as Nibiru was associated with the god Marduk. It is also the name of a hypothetical planet in our solar system.