Skull Rain shifts things from the deserts of the Middle East to the outskirts of Rio de Janeiro. Both of the new operators are from the Brazilian special police unit known as BOPE (Batalhão de Operações Policiais Especiais) and, as with the previous new characters, one is an attacker and the other a defender. Capitão, the attacker, has a special tactical crossbow that can fire incendiary bolts to ignite all the oxygen in a room and suffocate opponents (I don't think that's how air works?) and Caveira, the defender, can sneak up on enemies, incapacitate them, and reveal their fellow teammates.