Caesar is like a serpents egg: dangerous when hatched.
Act III Sc:1
"Et Tu Brute"
Caesar is tells Calpurnia to stand in Antony's way when he runs the course. Caesar speaks to Antony to tells him not to forget his speed. He reminded Antony of how the elders had said that if a barren woman was touched in the holy place, it would shake off the curse. Antony had said that when Caesar says to do something, it is done. The soothsayer overhears, and warns Caesar to Beware the ides of March. Caesar ignores his warning.
Act IV Sc: 1
Brutus contemplates on joining the conspiracy, but he finally comes to the conclusion of thinking of Caesar as a serpents egg: He may not be dangerous now, but he potentially could be. Brutus gets dragged into the conspiracy with the continuous nagging of Cassius.
Act V Sc: 5
"Brutus was the most honorable Roman"
After ignoring the previous hints of the Ides of March which Caesar ignored, and the suspicious activity going on around him. Caesar, and his "loyal' friends head to work. Caesar gets seated, and then starts getting requests,etc. Casca rises, and stabs Caesar, and they all continue to stab....Then he goes to Brutus to get help, who shrugs him off. Caesar says his famous line "Et tu Brute", then fall Caesar.
"Caesar is too ambitious".
Antony, Octavius, and Lepidus are gathered with a checklist of men they plan to murder for conspiracy. Lepidus agreed to have his brother killed, if Antony would allow his nephew to be killed. Lepidus is later sent to collect Caesar's will, and while he is gone...Antony plans to murder him.
Brutus and his men were resting on a rock, and Brutus was afraid of being overthrown by Antony and Octavius. Brutus had Strato hold his sword while he ran into it. Antony and Octavius came upon Strato and Brutus. Strato made the point that Brutus overcame himself, so that he died with "honor". Antony calls Brutus the most noble Roman soldier.
A theme would be jealousy. The conspirators have said that Caesar was "too ambitious". In my opinion, they too were ambitious. They tried to disguise their ambition, and make it loo k like they were doing things for the good of Rome. They flaunted Caesar's ambition to make it seem like they had a good reason for killing Caesar. I believe that they were just jealous, and they wanted to hide it to make it seem that they were honorable; which is very low.