Also known as the Mysteres and The Invisibles. Lwa comes from the French word Les Lois meaning The Laws.
The Lwa are spirits, intermediaries for the Supreme Creator Bondye (from French Bon Dieu, meaning Good God.)
Each Lwa is distinct with a unique personality. They have their own likes and dislikes, their own sacred rhythms, sigils, objects, colours, songs and dances.
They belong to families or nanchons (nations), which are similar to pantheons.
For example the Rada family come from the West African kingdom of Dahomey (which is now in the country Benin), whereas the Kongo family comes from the Congo region of Central Africa.
Unlike other intermediary beings, such as angels, Lwa are not prayed to. They are summoned into a perisyle (ritual space) by either a hounagn/mambo (priest/priestess) or a bokor/caplata (male witch/female witch) and served.
During the ritual, the Lwa will mount (possess) one of the participants. The mounted ritualist is called a horse, and is ridden by the visiting Lwa. This process can sometimes appear violent with horses flailing and convulsing. It has been likened to when Evangelists are filled with the Holy Spirit, but depending on the rider there is the risk of self-harm.
Once mounted, the horse's demeanour and speech will take on the characteristics of the rider. The ritualist in charge will identify the Lew and give them objects they're associated with,, such as a cane and pipe for the Lwa Legba.
During their visit, the Lwa is served and given offerings, they may give help or advice before departing.
An ABCs of Gods, Myths, and Superstitions.