In Shakespeare's Julius Caesar, which other man besides Caesar is ambitious?

Apart from Caesar himself, several characters in Julius Caesar are ambitious. Cassius is one of them. He flatters Brutus and convinces him to get rid of Caesar. He is clearly jealous of him, saying to Brutus, “And this man [Caesar] / Is now become a god, and Cassius is / A wretched creature and must bend his body.” Unlike Brutus, Cassius is not driven purely by honor. He knows that a takeover must be brutal....

Apart from Caesar himself, several characters in Julius Caesar are ambitious. Cassius is one of them. He flatters Brutus and convinces him to get rid of Caesar. He is clearly jealous of him, saying to Brutus, “And this man [Caesar] / Is now become a god, and Cassius is / A wretched creature and must bend his body.” Unlike Brutus, Cassius is not driven purely by honor. He knows that a takeover must be brutal. When Cassius gains power, Brutus accuses him of corruption and of having “an itching palm.” Cassius denies this, but his motives seemed venal from the beginning.

Mark Antony is another ambitious fellow. Because Antony has a reputation for partying, Brutus underestimates his ability to focus and manipulate. Brutus also generally assumes that others are like he is, straightforward and noble. He gives Antony a chance to speak at Caesar’s funeral, and Antony uses the opportunity to turn the people against Brutus. He then joins with Octavius to war against the conspirators who survive the commoners’ wrath. Antony reveals great arrogance and disdain for others when he coldly agrees to mark his nephew for death and refers to Lepidus as nothing more than “a property.”

There are also signs of Octavius’s aspirations. In spite of his youth (and Antony’s assertion that he has “seen more days than” Octavius), Octavius still stands up to Antony on occasion. He defends Lepidus and disobeys Antony’s order to take “the left hand of the even field” in battle. He simply tells Antony that he will take the right side and that he  is not trying to cross him. Octavius goes his own way. The young man’s designs become more apparent in Antony and Cleopatra. It is fitting that, in a play about power, ambition drives numerous characters in Julius Caesar, including the titular Caesar.