These were phantom lovers of men in North France. If their amours married others, the fadas ensured that he would die before consummating his marriage. If he did not, the lovers would inevitably drift apart anyway with the men losing their purpose of life without the fadas. Fadas were often worshipped with sacrifices, and were said to bring fertility.
On 31st December, the fadas would enter the houses of their worshippers bearing good luck in their right hands and bad luck in their left hands. The rooms would have been cleansed with the doors and windows left open and a white cloth on the table. Also on the table would be a vessel full of water or wine, a cup, some food, and a lighted candle or a wax taper in the centre.
Families who left good food for the fadas would receive good fortune, while those who gave them poor food would recive the opposite. Fadas were only occasionally said to be miniscule like British Fairies.