"Mermaid" is a planet that was only mentioned in the manga, and is said to be the original home planet of Sailor Mermaid and Sailor Aluminum Siren. It was devastated during Sailor Galaxia's conquest of the galaxy. These are the only pieces of information about this planet. Sailor Aluminum Siren helped Sailor Galaxia destroy her home planet for power after she was promised to be granted the ability of becoming a real sailor guardian.