At first I thought I would get no ideas for this prompt, because fantasy is not really my thing. In the end I just went all out with a little fantasy AU of my own – and I had lots of fun while working on it!
In this AU, we have these magical creatures who live in the wild as the children of nature. They have a human body, but they have the ability to consciously transform into their soul animal partially or completely, depending of their surroundings and how they wish to move. All of them have horns in their head, regardless of what animal they are (I don’t really have an explanation for this except that horns are cool).
Ai is a young duck boy who lives on land, but likes to spend time at the seashore. The moment he first catches a glimpse of the gorgeous shark boy Rin coming to the surface, he’s in love.
Shark people are often misunderstood because of their short temper and aggressive nature, but Ai sees that there’s more to Rin than his moodiness. It’s a bit tricky to befriend a child of water when Ai is not one himself, at least not a pure one (ducks are children of earth, air and water altogether). But he doesn’t give up.
It takes a long time to win Rin’s trust, but eventually the two of them are able to become friends and swim together in the sea. As days go by, Rin finds himself enamoured of this brave, beautiful duck boy.