The Antarctic Ocean Castle is the home of the Mermaid Princess, Karen, and her servants. The castle only appeared in episode 27 of Mermaid Melody Pichi Pichi Pitch.
Karen's Kingdom is at the South Pole. After defeating Gaito, Karen returns to her kingdom to rebuild it along with the sirens. The whole kingdom is ice, so it os known as "The Kingdom of Ice". It has many ice sculptures as it is located in polar regions.
The Kingdom of Ice has many purple starfish. Inside the castle are different shades of purple and Karen's shell throne.
Karen's room is in the highest tower of the Palace, with a balcony that has a lilac purple heart-shaped cushioned chair. Karen provided the subjects with protection.
They have the violet shades queue but do not have the bracelets that the mermaid princesses have in the queue.
What little we see is the throne room. It is all purple and has some columns that resemble the Parthenon in Athens. The castle is decorated with light-purple ice crystals.