| Charon Castle |
"Charon Castle" orbited the planet Pluto, and in the manga, it was the palace of Princess Pluto, given to her by Queen Serenity when she was born.
In Act 41, the Solar System Sailor Senshi called upon the power of their castles and directed it to the Holy Moon Chalice, which gave Sailor Moon the power to transform into Eternal Sailor Moon. Guardian Pluto greeted Sailor Pluto when she arrived in Act 45.
- The castle is named after Pluto's largest moon.