He appears briefly in two episodes of the second season and plays a major role in the third season. He is portrayed as a a womanizer and a playboy but is later discovered to actually be a eunuch. At the end of episode 3.14 ("Cherry Peck"), it is revealed that Costa does not have a penis. Early in the next episode he attributes this to a genetic disorder known as 5-alpha-reductase deficiency that he suffers as a product of incest. He is one of the suspects for being the Carver a serial mutilator, and eventually ends up being him and is discovered to be helped by the person investigating the crimes, Kit McGraw, who actually is his sister and incestuous lover.