Aqua Regina(アクア・レジーナ様 Akua Rejīna-sama) is the ocean goddess who makes quick cameo appearances to give the mermaid princesses a quick upgrade and new songs to defeat their enemies.
Thousands of years ago, Aqua Regina had used most of her energy to trap the Panthalassa in the darkness, unable to go on any longer. The Panthalassa then gave a cursed fate to two boys who were their descendents at the time. The power of the two combined was enough to destroy the world, and because Aqua Regina was lacking the strength, she was unable to break the spell given to the two. She then had no choice but to separate their powers and let them live separate lives in order to prevent the possibility of an apocalypse.
Aqua Regina has body length blond hair and blue eyes, strongly resembles Lucia. She wears a light blue crown, blue jewelry with red gems, and a see-through shawl with her big puffy white dress. She always has her staff with her, which has a big blue gem with wings on the top and wrapped with green vines and leaves.
- *Aqua Regina means "Queen Water"(not to be confused with "Aqua Regia", wich means "Royal water")