Frederico "Fredo" Corleone is a fictional character in Mario Puzo's 1969 novel The Godfather. Fredo is portrayed by American actor John Cazale in the Francis Ford Coppola 1972 film adaptation and in the 1974 sequel, The Godfather Part II. He is the second son of the Mafia don Vito Corleone (Marlon Brando and Robert De Niro). Fredo is the younger brother of Sonny (James Caan) and the elder brother to Michael (Al Pacino) and sister, Connie (Talia Shire). Corleone family consigliere Tom Hagen (Robert Duvall) is his informally adopted brother.The character of Fredo is weaker and less intelligent than his brothers and has little power or status within the Corleone crime family. In the novel, Fredo's primary weakness is his womanizing, a habit he develops after moving to Las Vegas and which earns his father's disfavor. In the films, Fredo's feelings of personal inadequacy and his inability to act effectively on his own behalf are character flaws leading to his demise. Source: Wikipedia (en)