Vito Corleone
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.