Mark Antony's strengths include being a strong orator. He is able to convince the crowd to turn against the conspirators and create a civil war with his "Friends, Romans, Countrymen" speech. He is a loyal friend to Julius Caesar and avenges Caesar's death. After telling Cassius and Brutus that he would gladly join them if they could explain why Caesar had to be killed, once Antony is alone with Caesar's body, he asks for forgiveness with, "Oh pardon me, thou bleeding piece of earth/That I am meek and gentle with these butchers!" He does, however, prove to be more ambitious than Cassius believed Caesar to be. Once the civil unrest began, Antony got together with Octavius and Lepidus to create a triumverate. Once things got going his way, though, he planned on getting rid of Lepidus. Antony was even ready to sacrifice "his sister's son" for his political gains.
Brutus' strength is that he is a loyal Roman above all else: before friendship, before family, before self. He joins the conspiracy because he is convinced by Cassius that Caesar is overly ambitious. In his oration after the assassination, he shows that he did care for Caesar with his words: "Because Caesar loved me, I weep for him....but as he was ambitious, I slew him". His major fault is that he is a bad judge of character. He believes that Antony is harmless, but soon learns differently.