Marc Antony is a superficial man:
- In Act II, Scene 1 in the orchard of Brutus as he takes charge of the conspiracy to kill Caesar, Cassius suggests that they also kill Marc Antony, but Brutus rejects his notion that Antony is ambitious, considering him a shallow man, saying that Marc Antony is merely "given to sports, to wildness, and much company" (2.1.89). In fact, he is described by Caesar himself as one who"revels long o'nights" (2.2.116).
- Although Antony is greatly grieved by Caesar's death as his soliloquy of Act III, Scene 1 depicts, he chooses to flatter Brutus so that he will survive: "First, Marcus Brutus, will I shake with you,"(l.185), and telling him he "doubt[s] not" of his wisdom.
Marc Antony is also a politico:
- He capitalizes upon opportunities for his own advancement. In his funeral oration, he cleverly turns the plebians against Brutus and the other conspirators, and, although declaring his great love for Rome, Antony incites the Romans to civil war, capitalizing on an opportunity for power.
- With Octavius Caesar, the nephew of Julius Caesar, and M. Aemilius Lepidus, Antony forms the triumvirate that battles against the armies of Brutus and Cassius. In his quest for power, Marc Antony has no qualms about taking any advantage he can. In Act IV, for instance, despite having assured the Roman people that much of Caesar's money would go to them, Antony tries to extract the money from Caesar's will for the triumvirate.
- He displays no loyalty to this triumvirate, however; for, after Lepidus leaves, he disputes with Octavius the usefulness of Lepidus,
This is a slight unmeritable man,
Meet to be sent on errands; is it fit,
The threefold world divided, he should stand
One of the three to share it? (4.1.13-16)
- But, Octavius comes to the defense of Lepidus, an action that the politico Antony does not forget because when Octavius shows that he is a Caesar, Antony remembers this in Act V after Brutus dies. Anticipating that in a like manner, Octavius will show respect for the nobility of Brutus--as he certainly does in the final lines of the play--Antony lauds the fallen enemy, calling him "the noblest Roman of them all" (5.5.74)
In addition to this answer, I think you should read Antony by Plutarch.