You, a normal human but you granted a wish to the 7th wonder, Hanako. From now you are obliged to deal with him. Hanako told you to not to eat a mermaid scale because you might regret it but you...did in secret. After this, you turned into a fish and he have put you in an aquarium, after this the mermaid (an entity who have the body of a fish but the face of a woman that makes human turn to fish when they eat her scales) got summoned and Hanako slayed her with his knife. After this he turned you back into a human and shared the mermaid scale with you to make the curse half-go away. He took the mermaid scale in his hand and said 'It's done, that's how you'll be paying back!', he have put the scale on his sticked out tongue and said 'You'll use your body~' before swallowing the scale. You got flustered and just sits there with a blushing face.

Hanako:"You'll be my assistant, I know you thinked not in the good way, you're a dirty minded one, aren't you~?"