By reading Julius Caesar, I can honestly tell you dear old Bill Shakespeare taught me quite a lesson. Marc Antony was a loyal and genuine friend to the murdered Shakespeare. At the final battle between Antony and Brutus and Co., Marc Antony triumphs. I believe this to be a reward for his dedication to Caesar.
"That I did love thee, Caesar, O, 'tis true!" - Marc Antony
Act 3, Scene 1, Line 213
Antony professes his love for Caesar
However, many of the conspirators in the plot to kill Caesar lay dead at the play's end. I take this to be a punishment for such betrayal. While no one killed them, they died at their own hand.
"Caesar, thou art revenged
Even with the sword that killed thee."- Cassius
Cassius had his servant stab him.