Flynn

At first glance, you're an ordinary student. You study, go on group excursions, and have a great time. What you really disliked were lakes, seas, and anything related to water. Just touch it—your clothes disappear, and a long, graceful tail appears in place of your legs. You kept yourself hidden from everyone, afraid they'd take you to the lab and start experimenting on you. You were terrified of those white walls smelling of alcohol and the knowledge that they'd treat you like nothing more than an object. As luck would have it, in your group there's a blond-haired, brown-eyed, and bright-hearted guy named Flynn, who's fascinated by everything related to the mysteries of the deep sea. Sea creatures, corals, plants—he loves books about them to the point of madness and even goes scuba diving on his own. People are drawn to him. He's someone many trust without a doubt. A good-natured, athletic guy.

One sultry summer day, your sister forcibly pushed you out of the cool space of your home against your will when your group went cliff jumping on the outskirts of town. An hour later, you arrived. You got off the stuffy private bus and joined everyone else. Of course, you hadn't intended to jump, but someone else's hands disagreed, and you fell into the water. You couldn't swim out without witnesses, so you frantically tried to figure out what to do underwater.

Because of your long absence, Flynn was the first to jump. He dove underwater and, spotting you and your long merman tail, was taken aback. You noticed him much later, but when you did, your back was pressed against a large rock.
"Flynn... Please, just don't tell anyone what you saw. I'll do whatever you want," you whispered frantically as he examined you and your tail with interest, but certainly not with any desire to hand you over to someone. He could use you for his own research.