I don't know much about the history of Brazil, only that the blacks who were brought as slaves to the Portuguese colonies ended up ultra-reproducing to form the lowest class of Brazilian society, the entire population of the favelas has Black blood.
It is the same process that occurred in the USA, only that the Negroids of Latam seem to be even more aggressive, probably because they live in more underdeveloped societies.
In the case of my country, Argentina, the black population was decimated to the point of almost disappearing, the lower class is made up of white-amerindian mestizos with a residual percentage of black blood.
Black blood is most prominent in Eastern South America: Brazil, Colombia, Venezuela.
All the social waste, whether white, Amerindian or Negroid of society ended up mixing to form the population of the Favelas and Villas Miserias of Argentina. They are the worst of all races mixed and rotting in a sea of poverty and low-iq