A Protagonist is the main character of a story, and the main playable character in the Mafia Series.

Traditionally, a protagonist is the main figure of a piece of literature or drama and has the main part or role. Alternatively, the phrase denotes a primary advocate of or proponent for a cause or movement. The main character can be a hero or a villain in a story - it is just the character with the lead role. In literature, the protagonist is characterized by his/her ability to change or evolve.

It should be pointed out that the protagonist is not always the hero of the story, as implied in the Mafia games. He/she may commit crimes of some sort, but he/she is still considered the lead character, and is known to help out his/her friends, allies, or close associates.

The opposite of a protagonist is an antagonist, which is the main enemy of the protagonist and works against the protagonist and his actions. Again, this can be a villain or a hero, though usually a villain.

Current list of Mafia protagonists

Tommy Angelo

Tommy Angelo
Thomas "Tommy" Angelo is the protagonist of Mafia: The City of Lost Heaven. Originally a cab driver, he is forced to join the Mafia due to a combination of unpleasant circumstances. He later became a soldato for the Salieri Crime Family. By the end of the game, he betrayed Salieri and testified against him in order to protect his family. He was then murdered 13 years later.
Vito Scaletta (Mafia II)

Vito Scaletta
Vito Scaletta is the protagonist of Mafia II. He is an up-and-coming gangster in the Empire Bay criminal underworld who was caught in a botched robbery and forced to join the army during World War II. After his return, he rejoins his childhood friend Joe Barbaro and the two eventually became made members of the Falcone Crime Family.
Jimmy (Mafia II)

Jimmy is the protagonist of the DLC's The Betrayal of Jimmy and Jimmy's Vendetta. He is a contract killer and enforcer who will accept any job for money. From trashing cars to shooting up buildings he does it all. He was betrayed by his employers and was sentenced to 15 years in prison; however, he escaped during a prison riot and succeeded in taking revenge on the ones who betrayed him.
Joe Barbaro

Joe Barbaro
Joe Barbaro is the secondary protagonist of Mafia II, and the protagonist of the DLC Joe's Adventures. He is Vito's childhood friend and together they try to live the life of the criminal underworld.

Marco Russetto
Marco Russetto is the protagonist of Mafia II Mobile. He is a member of the Salieri Crime Family who fled to Empire Bay after Tommy Angelo agreed to testify against the Salieri family. His only known relative is his uncle Vincenzo.
Lincoln Clay

Lincoln Clay
Lincoln Clay is the protagonist of Mafia III.