Marc Antony is a complex character, one ripe for analysis. For, there seems to be a duplicity to Mark Antony that is suggested in his funeral oration as he manipulates the crowd with rhetorical devices and as he implies the treachery of Brutus and the others with the repetition of "But Brutus is an honorable man; so are they all, all honorable men."
Later in the play, the seemingly loyal and devoted friend of Caesar shows no loyalty to a family member as he is willing to sacrifice his nephew in exchange for the life of Lepidus's brother in Act IV: "This is a slight unmeritable man,/Meet to be sent on errands" (IV,i,12-14)
Then, although the earlier scenes in which Antony vows revenge and turns the crowd against Brutus and the others as well as proscription scene may supply evidence that Antony is self-serving and cruel, in the last scenes of the play, he honors Brutus by stating that Brutus was the only one of the conspirators who acted for the general good, rather than out of envy of Caesar. In fact, Antony calls Brutus "the noblest Roman of them all" (V,v,68).
Have you checked the link to the How To Analyze a Character here at enotes? It's below. Also, when analyzing a character in any piece, be sure to think about what he says, does, thinks, and the way other react to and think about him. Antony was correctly identified as Caesar's right-hand man, but misjudged as someone who would follow the conspirators after Caesar's death. Cassius did not trust Antony and suggested that he, too, be killed. Brutus is the one who said Antony need not also die. Brutus also misjudges the effect that Antony's powerful speech about Caesar at the funeral would have on the commoners.
What should I talk about if I compare and contrast Calpurnia and Portia?