Fireflies are stars that have landed in the world. They gently dance their thin wings and hover around you.
Generally speaking, fireflies only live in fields or near clear pools. If you are lucky enough to see one in the city, it means that someone cares about you and entrusts this beautiful elf to express her thoughts.
Well, actually, fireflies are just simple insects that neither appear in cities for no reason nor follow them around.
All we can say is that what is dancing above your head is not a living thing, but...
Ghost...