Cures:
* Cure Bloom: Saki Hyuga
* Cure Egret: Mai Mishou
Mascots:
* Flappy: A fluffy pink penguin who is the mascot of the Mermaid Princess.
* Choppy: A blue penguin who is the assistant of Flappy.
Other Important Characters:
* Kenta Aoi: Saki's classmate and best friend.
* Karen Aoi: Kenta's younger sister.
* Michiru Mishou: Mai's older sister.
* Nagi Misaki: Saki and Mai's classmate who later becomes a Cure.
* The Mermaid Princess: The princess of the ocean who needs the Cures' help.
* Dark Fall: The main antagonist who is the evil counterpart of the Mermaid Princess.
* Dark Cure: The evil version of Cure Egret who serves Dark Fall.
* The Mermaid Princess's Mother: The previous Mermaid Princess who helps the current Mermaid Princess and the Cures.
This list includes the key characters in the story, and you can find more information about them on the official website or wiki.