Depending on how you look at it, there are two ways to view the appearance of the ghost.
1. You could view Caesars appearance as a bad omen for Brutus.
2. You could also view it as a manifestation of Brutus' guilt for killing Caesar. He truly admired Caesar but thought that his death would make Rome a better place.
Et Tu Brutus
If so, we are not shown it. But Caesar and Brutus had a special relationship which makes the ghost's visit to Brutus make more sense than a visit to Cassius would.
The reason Antony does this is to make the citizens/ the poor to go and against Cassius, Brutus, and the conspirators. :D
The ghost of Julius Caesar appears to Marcus Brutus in Sardis and Philippi.
He gets visited by the ghost of Caesar.
Caesars ghost
to tell brutus that he would see him at philippi
to foreshadow the defeat of brutus in the battle at phillipi
Brutus sees a vision of Caesar's ghost, at the end of Act Four.
Caesar's ghost says he comes to tell Brutus that he (Brutus) will see him (the ghost) at Philippi. But this is not what he means. What he means is that Caesar will be revenged on Brutus at Philippi
Caesars sole or ghost
Brutus, the senators, and Cassuis.
Brutus
Brutus and Antony.
brutus
He was Julius Caesars nephew and killed Julius Caesar with a knife.
Marcus Brutus