In Act 1, Scene 2, Cassius pulls Casca towards him & Brutus after Caeser had left. Cassius asks Casca what happened at the ceremony after the race for the Feast of Lupercal. Casca tells them "Mark Antony offer him a crown"(I:ii:ln 235-236). "He put it up the third time by; and still as he refused it, the rabblement hooted, and clapped their chopt hands," (I:ii:ln 242-244). Caeser was trying to make the cowd say that he should be the king of Rome but it ends up failing. This is where some of the conspirators think that Caeser is ambitious.
Act IV: Sc iii
In Act 2, Scene 2, Decius exploits Caeser's flaw of being cocky & arrogant. "Break up the Senate till another time, When Caeser's wife shall be met with better dreams." (II:ii:ln 98-99). Decius manipulates the dream and says how stupid the idea is of not going. Using Caeser's arrogance about how he can't be stopped, he tricks Caeser into going to work so that way the conspirators can kill him.
Act V: Sc iii
In Act 3, Scene 2, Antony is convincing the crowd that the conspirators had killed Caeser for no reason & should be punished for their crime. He doesn't say it out write because "Brutus is an honorable man, So are they all, all honorable men." (III:ii:ln 83-84). THe words themselves aren't going to get the point across. What actually gets the point across is how he says the words.
THEME Act V: Sc IV
Act 4, Scene 3, Brutus & Cassius are angry at each other because they so called wronged each other. Brutus killed Pella, 1 of Cassius' men, for taking bribes from the Sardians. Brutus says that they shouldn't be taking bribes. Brutus says that Cassius has wronged him by not giving him the money to pay for his troops. In the end they make up though. "In this I bury our grief, Cassius. My heart is thirsty for that noble pledge." (IV:iii:ln 158-159).
Act 5, Scene 3, Cassius realizes that he has just sent his best friend to his death. He tells Pindarus "Now be a free man, and with this good sword, That ran through Caeser's bowels, search this bosom." (V:iii:ln 41-42) Cassius makes Pindarus kill him & Pindarus does so without hesitation. This shows both the conspiracy starting to meet its end & it also shows Cassius' cowardliness.
Act 5, Scene 5, Antony & Octavious have defeat the honorable men of Cassius & Brutus. Antony comments "This was the noblest Roman of them all." (V:v:ln 68-69) Even the noblest Roman of them all, who did the wrong thing for the reasons, couldn't escape karma. The theme of Julius Caeser is that no matter of how good of a person you are, you will never truly get away with a crime.