Enotes has many excellent sources for your question, so also look there, but I will give you a brief answer! Brutus is one of the main conspirators, yet he assists in the assassination of Caesar out of a sense of honor and for the good of Rome, truly believing Rome is better off without Julius Caesar. On the other hand, Cassius, also a main conspirator, is ambitious, and even Brutus accuses him of having an "itching palm," being greedy. He is shrewder than Brutus. Brutus believes in the goodness of people and trusts Mark Antony even after Cassius warns him of Antony's character. Both men end up committing suicide. Brutus's misplaced trust is a main cause for the failure of the conspiracy!
Marcus Brutus -
� A supporter of the Republic who believes strongly in a government guided by the votes of senators.
� While Brutus loves Caesar as a friend, he opposes the ascension of any single man to the position of dictator
� He fears that Caesar aspires to such power.
� Brutus’s inflexible sense of honour makes it easy for Caesar’s enemies to manipulate him into believing that Caesar must die in order to preserve the republic.
� While the other conspirators act out of envy and rivalry, only Brutus truly believes that Caesar’s death will benefit Rome .
� Torn between his loyalty to Caesar and his allegiance to the state, Brutus becomes the tragic hero of the play.
� Brutus emerges as the most complex character in Julius Caesar and is also the play’s tragic hero.
� He is a powerful public figure, but he appears also as a dignified military leader, and a loving friend.
� In a moment of na�ve idealism, he ignores Cassius’s advice and allows Antony to speak a funeral oration over Caesar’s body
� A talented general and long-time acquaintance of Caesar
� Dislikes the fact that Caesar has become godlike in the eyes of the Romans.
� He slyly leads Brutus to believe that Caesar has become too powerful and must die, finally converting Brutus to his cause by sending him forged letters claiming that the Roman people support the death of Caesar.
� Impulsive and unscrupulous-- shrewd opportunist-- proves successful but lacks integrity.
brutus was the good friend of caesar but cassius and other conspirater influnce him agains caesar.but brutus wanted the welfare of rome.so,come into the voice of cassius.
The treachery of Cassius and his betrayal make him the plays worst character...while Brutus has acted in the benefit of the people..(he thinks he is doing so)..cassius has acted in his own...hunm tell u the rest later..