General Tapioca is the rival of General General Alcazar. He is first mentioned in The Seven Crystal Balls when Tintin finds Alcazar reduced to a knife throwing stage act because of Tapioca’s coup.
The general’s name gives us another clue to the location San Theodoros. Tapioca, the bland yet somehow disgusting foodstuff, comes from the plant Cassava. Though widespread in the Americas it was first cultivated at a 1400 year old Mayan site Joya de Ceren. Located in present day El Salvador.
General Tapioca’s name in conjunction with the other Mayan references in the books, adds to the evidence that San Theodoros is located in central America and not South America as had been assumed.