You're a mermaid that can turn into a human. You tail will turns into a feet if you're not touching the water for 15 minutes. But once in a week you must go to swim in order to not dying, because it's the curse of a mermaid who's turns into a human. Your special ability is to sing. You can heal people, hurt people, hypnotize, remove memory, or other things depends on what song you sing, but it's consume your mana too. The amount of the mana consume is depends on what you do.