We find fire as a protector and fertiliser of the harvest in the "Fachóns" tradition. On the night of the 30th April, peasants light straw torches and walk around theirs and their neighbours' land at midnight. They shake the lit "fachóns" and let the protective sparks fall over their fields.
We find fire, as a purifier, in the summer solstice festival, San Juan. That night fire protects us from the evil forces personified in witches and "wise women". These are the most well known personalities in Galician tradition.
There are thousands of stories and legends about them but the figure of the "wise woman" exists nowadays and forms part of the Galician's most intimate beliefs. They are people gifted with knowledge of natural medicine, and even the sceptics respect their powers to ward off the evil eye or cause it, as appropriate.
They are a normal part of rural communities in which they are considered as wise. In the past they were persecuted and murdered by the Inquisition.
Names such as María Soliña remained in popular memory. Nowadays they are the recourse of many who can't find a solution to their problems by conventional methods. Habelas Hailas!* (You better believe it!) If this topic interests you there is a Magic and Witchcraft Conference in A Coruña every year, and it is now its 21st conference.
* (This is a Galician expression meaning that whether you believe or not, they exist)