Minazuki Karen

Karen is one of the official characters of the Pretty Cure franchise. Her alter ego is Cure Aqua (キュアアクア).

Canon
Karen is admired by other students due to her calm and stoic nature. This, however, is her outer character--she is actually very lonely, especially when thinking about her parents, whom she secretly misses. Because she has known Komachi for such a long time, Karen often feels responsible for being there for her; to an extent, she feels this way about everyone, believing it to be a natural responsibility of the president of the student council. Because of her position, Karen is able to memorize all the names and faces of all the Cinq Lumières students, and also easily takes responsibility when something happens to the school, as seen in the second episode where she wants Nozomi to explain what happened to the library the other day.

Fanon Description by Caramelangel714
In the Mega Man crossover, her special alter ego is Dive Aqua (ダイビングアクア), combining with Dive Man's power.

Fanon Description of Samueljoo
In the Super Sentai, she was Takeru's girlfriend (later, wife) and Samuel Nakaoka the Second's (kinda) hateful event butler. With the Doom Immortal's demise, she takes Samuel as a butler much as Samuel Nakaoka's shocked and dismay. In the worst part her running gag was Samuel Nakaoka the Second as AllDragonFormation take off his helmet before become violently fighter because she hates Samuel Nakaoka's girly face as well he tried to take off his helmet.

Appearance
Karen has dark blue eyes with thick eyebrows. Her matching colored hair is worn loose with some strands over the left shoulder and her bangs brushed to the left. In GoGo! her casual outfit is a bluish-gray top and skirt with a bow on the back, and navy heels.

In ''Yes! Pretty Cure 5: Kagami no Kuni no Miracle Daibouken!'', Karen wore a light purple jacket with fluffy trim over a dark teal outfit with light grey boots.

As Cure Aqua, her hair turns bright blue, with her hair growing out into a straightened ponytail held with a blue butterfly adorned by a red gem. She also gains blue butterfly earrings. Her outfit is styled like Cure Mint's, a white mini-dress with blue lining and bow around the waist and pale yellow straps circling the off-shoulder sleeves. These are trim with pale blue ruffles to match the secondary skirt layer, and on the chest is a butterfly, but this one is pale yellow. She also gains dark blue shorts and blue boots with a butterfly, and gloves to match her dress with a light blue butterfly on the hand, her Pinky Catch worn on the wrist.

As Super Cure Aqua, the ruffles on her sleeves and boots grow longer while her skirt gains an extra layer. She has large blue butterfly wings.

In GoGo!, her earrings and shorts remain the same, while her hair butterfly loses it's gem in favor of a magenta flower. Her gloves and boots change in style, along with her chest butterfly, which connects to her CureMo. Her dress loses it's outer layer in favor of a pastel blue vest lined in blue, accenting the new straps of her full sleeves. The ruffles have become pale chiffon.

As Super Cure Aqua, her outfit is similar to Shining Dream's. She has pale pink roses on her chest and her hair ornament and small gold wings.

Trivia

 * According to the Mega Man crossover, she have a bit of a love interest of Dive Man.
 * Aqua has a bit hatred of Samuel for being such a stupid or took anything of the fridge.