Sergeant Diaz is a character who makes a one-time appearance in the Season 1 episode titled "Mad Over Miami".
Sergeant Diaz is Colonel Fernandez's subordinate. During the ransom operation where Fernandez is planning to exchange political prisoners Ramon Collarzo and Father Gomez for two million dollars, Diaz acts as his deputy, relaying his commands and offering advice.
During the episode, Diaz is seen with two yellow stripes on his epaulettes, indicating that he is a Sargento de Tercera or Sergeant third Class. The letters FAR are also seen, and stand for Fuerzas Armadas Revolucionarias -- the Revolutionary Armed Forces (of Cuba). He carries a Valmet M71S.