Water Princess

Water Princess is a princess of an as of yet unknown kingdom within The land of Ooo. She plays a minor role in the 4th issue of the Adventure Time Comic where at the request of Princess Bubblegum she uses her powers to create a lake for Desert Princess's new kingdom in Ooo.

Appearance
She has long hair that seems to resemble seaweed. The base of her gown looks like a mermaids tail. She also wears a sea urchin like tiara with pearls to show her royal status.

Princess Bubblegum
The two princesses seem to know each other and have a friendly relationship. It was upon P.B's request that she used her powers to make a lake for Dessert Princess.

Trivia

 * Do to her appearance, title and power over water, she could be the first "water elemental" to appear in any continuation of the series.