The Loa (also Lwa or L'wha) are the spirits of the Vodou religion practiced in Haiti, and other parts of the world. They are also referred to as the Mystères and the Invisibles. They are somewhat akin to saints or angels in Western religions in that they are intermediaries between Bondye (Bon Dieu, or good god)—the Creator, who is distant from the world—and humanity. Unlike saints or angels however, they are not simply prayed to, they are served. They are each distinct beings with their own personal likes and dislikes, distinct sacred rhythms, songs, dances, ritual symbols, and special modes of service. Contrary to popular belief, the loa are not deities in and of themselves; they are intermediaries for a distant Bondye.
As a way to keep their European masters from interfering, and to appease the authorities who prevented them from practising their own religions, the African slaves in Haiti syncretised the Loa with the Roman Catholic saints - so Vodoun altars will frequently have images of Catholic figures displayed. For example, Papa Legba is alternately St. Peter or St. Lazarus, Ayizan is Saint Clare, and so on. Syncretism also works the other way in Haitian Vodou and many catholic saints have become Loa in their own right, most notably St Philomena, St Michael the Archangel and St John the Baptist.
Certain Loa display very distinctive behaviour by which they can be recognised, specific phrases, and specific actions. As soon as a Loa is recognised, the symbols appropriate to them will be given to them. For example Erzulie Freda will be given a mirror and a comb, fine cloth or jewellery; Legba will be given his cane, straw hat and pipe; Baron Samedi will be given his top hat, sunglasses and a cigar.
Once the Loa has arrived, fed, been served, and possibly given help or advice, they leave the peristyle. Contrary to the Western perception of possession, a Loa has no need to remain in the horse (possessed ritualist). Certain Loa can become obstinate, for example the Ghede are notorious for wanting just one more smoke, or one more drink, but it is the job of the Houngan or Mambo to keep the spirits in line while ensuring they are adequately provided for.