Who is Jacinto das Chagas from The Viceroy of Ouidah and what is their importance?

Jacinto das Chagas is one of the former slaves from Brazil who arrive on a ship and are welcomed to Ouidah by Francisco. Jacinto, who is personable and good with numbers, becomes Francisco's assistant, but he soon turns on his employer and sets up a competing business, with the help of the king. Either Jacinto or the king's men poison Eugenia's mother, Luciana, and Francisco's right-hand man, Taparica. Jacinto is a smooth-talking, treacherous liar who is willing to give his daughter in marriage to the king to get business leverage. He is just the sort of person to succeed in Dahomey.