Papa Legba is the lwa (spirit) who stands at the crossroads and keeps the gate between the world of human beings and the world of the spirits, and in Haitian Vodou no ceremony can proceed until he has been saluted first. Because he holds the key to the barrier between the two worlds, it is Legba who must open the way before any other lwa can come through to be present at a service and to communicate with the living; he is therefore honoured at the very beginning of ritual, invoked to remove the barrier so that the spirits may pass. He is imagined as an old man, often poor and lame, leaning on a cane or crutch, with a straw sack over his shoulder, and he is associated with the sun and with the crossroads where paths meet.
Papa Legba's Haitian Vodou identity is often linked, through the syncretism that developed under colonial-era Catholicism, with Saint Peter, keeper of the keys to heaven, a natural match for a spirit who alone opens the gate between worlds. He belongs to a wider family of related crossroads and gatekeeper figures found across the African diaspora, most notably Eshu-Elegua of the Yoruba-derived traditions of Cuban Santeria and Nigerian Ifa, and Exu of Brazilian traditions such as Umbanda and Quimbanda; while Vodou practitioners, Santeros and other diaspora communities generally regard these as distinct spirits belonging to their own separate traditions rather than as one single figure under different names, scholars of Africana religions note the shared underlying pattern, a trickster-messenger who must be honoured first at any crossroads between the human and spirit worlds.