Vodou revolves around spirits known as lwa. Typically deriving their names and attributes from traditional West and Central African divinities, they are equated with Roman Catholic saints. The lwa divide up into different groups, the nanchon ("nations"), most notably the Rada and the Petwo. Various myths and stories are told about these lwa, which are regarded as subservient to a transcendent creator deity, Bondye. This theology has been labelled both monotheistic and polytheistic. An initiatory tradition, Vodouists usually meet to venerate the lwa in an ounfò (temple), run by an oungan (priest) or manbo (priestess). A central ritual involves practitioners drumming, singing, and dancing to encourage a lwa to possess one of their members and thus communicate with them. Offerings to the lwa include fruit, liquor, and sacrificed animals. Offerings are also given to the spirits of the dead. Several forms of divination are utilized to decipher messages from the lwa. Healing rituals and the preparation of herbal remedies and talismans also play a prominent role.