Who they are, in Umbanda teaching
Umbanda holds that these spirits knew the suffering of slavery firsthand and reached spiritual liberation through an inward awakening well before any legal emancipation. Because of that, the tradition associates their commemoration with May 13, the date Brazil's 1888 law abolishing slavery was signed, even though the freedom the tradition ascribes to them is described as a spiritual one attained earlier, while still incarnated.
Within Umbanda cosmology, Pretos Velhos manifest through mediums as elderly figures, often shown bent with age and carrying a pipe, and are understood to have retained from their African roots a body of knowledge about healing, plants, and the natural elements. "Velho," old, is glossed in this context less as a literal age than as a mark of lived wisdom.
Their place in the tradition
Practitioners regard Pretos Velhos as among the most loved and consulted spirits in Umbanda, known for patience, humility, and comforting counsel rather than dramatic intervention. Devotees address prayers to them, often naming a particular Preto Velho or Preta Velha they feel a personal connection to, asking for guidance through hardship — a devotional practice belonging to Umbanda rather than to Santo Daime itself.
Further
The old black spirits — understood in Umbanda as the souls of Africans who were enslaved in Brazil and who work now in charity, giving counsel and healing. They are pictured bent under the weight of what they know, white-haired, with a pipe; in the African sense that lies behind the figure, velho means experienced rather than aged. Their day is 13 May, chosen in analogy with the signing of the Lei Áurea that ended slavery in Brazil — though the sources are careful to say that the liberation the day marks is held to have happened inwardly, not in law. They appear in the Umbanda works of some Daime lineages.