The Forbidden Castle was an ancient castle on Munto Codru near the planetary capital Capital Codru which was built by a long-extinct alien civilization prior to the arrival of the planet's sapient species the Codru-Ji. It was filled with a long network of mazes and corridors. Its rock walls which were decorated with symbols and petroglyphs were carved so thinly that they appeared to be translucent.
Most Codru-Ji avoided the castle as they considered it be the domain of evil spirits. During their trip to Munto Codru, Jaina, Jacen and Anakin Solo visited the castle while their mother Chief of State Leia Organa Solo was taking part in talks with local officials.
- The Crystal Star (First appearance)