Kill Sailor Moon
Regulus was a youma created by Nephrite who only appears in episode 19 of the anime.
In the first anime, Nephrite consulted the stars and learned about Sailor Moon's weakness: her love for Tuxedo Mask. This gave him the idea to pose as Tuxedo Mask in order to lure Sailor Moon out. He then sent letters to all of the girls in the Azabu-Juuban area.
When Sailor Moon appeared at the Shinjuku MS Department Store in order to save Naru, Nephrite called on the power of Regulus, creating the Youma. He charged at Sailor Moon, when Tuxedo Mask came and the two got into the elevator, only to reveal that it was Nephrite's intention for them to run into the elevator so he could then kill them. Once this was accomplished, Nephrite recalled Regulus.
- He is the only undefeated monster of the week in the entire anime.