Water Princess

Water Princess is a princess of an unknown kingdom within Ooo. She plays a minor role in Volume 1 of the Adventure Time Comics where at the request of Princess Bubblegum she uses her powers to create a lake for Desert Princess' new Kingdom in Ooo. She later appears at the princess tea party in Volume 4 to put out the flames Magic Man started, and helps Princess Bubblegum execute her plan against Magic Man later in the same Volume.

Appearance
Water Princess has long hair that seems to resemble seaweed. The base of her gown looks like a mermaids tail, and has bare feet poking out from the bottom of her dress. She also wears what seems to be a water lily tiara with pearls to show her royal status. She has very pale blue skin and knife-like teeth, like Lamprey Princess'.

In Volume 4 of the Adventure Time comics, she is shown to be a mermaid underneath her dress, depicted when she has armored up with the other princesses to battle Magic Man. She seems to be able to switch between a mermaids tail and bare feet at will.

Relationships
Princess Bubblegum

The Two princesses seem to get along and have a friendly relationship. It was upon Princess Bubblegum’s request that she make a lake for the Desert Kingdom.

Lamprey Princess

They seem to have a good relationship, as they were next to each other when she was making the lake.

Choose Goose

She and Choose Goose seem to be on good terms, as he was playing with her in the water happily.