|This article is about the star α Geminorum. For the Youma Castor, see Castor.|
Castor, also known as α Geminorum, is a sextuple star system located around 50 light years from Earth. The component stars (two white dwarfs and four low-magnitude red dwarfs) together form the second brightest point in the constellation Gemini. The star system was mentioned in the anime episode "Protect the Children's Dreams! Friendship Linked by Anime."
Castor and Hiromi Matsuno
Castor was one of two stars controlling the energy of the animator Hiromi Matsuno; the other star being Pollux. Nephrite used this knowledge to predict a peak in her energy, and planned to exploit and ultimately steal her life energy with the help of his two strongest Youma, also called Castor and Pollux. The essences of both Youma were implanted into Hiromi's pencil.