Cercei

Cercei is a strange creature, almost like a mix of a goat and a rabbit, with a strong affinity for water. Her coat of swirling blue and flecks of white is the result of magic. She was once a human, a long time ago. She was thrown off a ship, believed to be the cause of the furious storm they were caught in. As she drowned she was visited by the actual cause of the storm, a witch, a goddess, and was given a choice. She chose to become an animal agent of the ocean’s fury.
As an agent of the sea, Cercei has strong hydrokinesis that is stronger the closer she is to the ocean, and more so the closer she gets to the Mariana Trench (because that’s where all powerful sea beings reside or originate from of course). She fights sailors and sinks ships, angry at all who seek to harm the seas.
She has travelled the world via coastlines and rivers, and does so over and over and she does the ocean’s bidding, and communes with other water based beings.
Cercei is immortal. She bleeds water, the sea. She is near immune to all temperatures (she can feel it but it can’t harm her any more then it can harm something built for that environment).