In Act V, what is the importance of the characterization of Octavius?
In Julius Caesar, Caesar's heir-apparent is Mark Antony. It is Antony who is anointed Caesar's successor by the mob (Act III, Scene 2), and Antony who is the senior to Octavius (Act IV, Scene 1). However, a question mark hangs over Antony's head -- we know from his quick and cunning response to the conspiracy that he is not merely a light-headed party animal, as Brutus has carelessly characterized him, but we are left unsure as to how solid he will be in the long term. His cynical comments about Lepidus make us wonder whether he can truly command the loyalty of those he must lead (Act IV, Scene 1):
And, in some taste, is Lepidus but so:
He must be taught, and train'd, and bid go forth;
A barren-spirited fellow, one that feeds
On objects, arts, and imitations,
Which, out of use and staled by other men,
Begin his fashion. Do not talk of him
But as a property.
Octavius may think this way of some of those he deals with, but he will never be so impudent as to say it out loud. This gives him greater leadership potential than Mark Antony.
Octavius' characterization in Act V reinforces the impression given earlier in the play that in spite of his youth, he is a talented, solid, and cautious leader who can inspire confidence among his subordinates. In the very first lines of Act V Scene 1, we learn that Octavius has predicted the movements of the enemy better than Antony has:
Now, Antony, our hopes are answered.
You said the enemy would not come down,
But keep the hills and upper regions.
It proves not so.
He then insists on keeping to the right in the battle, an arrangement that leads to victory, albeit indirectly:
O Cassius, Brutus gave the word too early,
Who, having some advantage on Octavius,
Took it too eagerly. (Act V, Scene 3)
When final victory is won, Octavius recruits everyone in Brutus' service into his own ranks (Act V, Scene 5):
All that served Brutus, I will entertain them.
Fellow, wilt thou bestow thy time with me?
And Octavius is given the final word in the play, indicating that his opinions will count the most in disposing of the results of the victory:
According to his [Brutus'] virtue let us use him
With all respect and rites of burial.
Within my tent his bones tonight shall lie,
Most like a soldier, order'd honorably.
So call the field to rest, and let's away,
To part the glories of this happy day. (Act V, Scene 5)
Thus, throughout Act V of Julius Caesar, Octavius is presented as not only Mark Antony's equal but in some sense his superior, despite his relative youth. He is more stable and mature, and he seems to see further into the future than the mercurial Antony. Even though there is little hint of hostility between the two in this play, the characterization of Octavius leaves us in little doubt of which one of them will prevail if they compete head to head, as they will in Antony and Cleopatra.