Fairies of sorrow grieve all the night, commiserating with the suffering of earth's children, singing solemn songs. Come morning, however, the fairies disappear with the light, transforming into new fairies of light and joy.

Legend holds that fairies of any species will become fairies of sorrow given enough tragedy, including the tragedy of disbelief in them, which may explain the appearance of sorrow fairies. The fairies allegedly have a therapeutic effect on unhappy people, as if the fairies absorb the misery upon themselves, relieving the human of it; the fairies' songs also calm and relax humans.