Julius Caesar is its own frame of reference, and a knowledge of Roman history is not essential to an understanding of the play. However, Shakespeare does construct the character of Octavius by highlighting those aspects of his personality that will predominate later in his political and military conflicts with Antony and in his role as the Emperor Augustus. In order to stabilize the political situation in Rome following the assassination and to solidify the triumvirs' control of government, Octavius is willing to conduct a ruthless reign of terror during which the opponents to the triumvirs are methodically slaughtered, but not all of those on the proscription list are actual enemies. Some are simply wealthy Romans who are condemned as "traitors" and executed in order that the triumvirs may confiscate their estates as a means of raising money to finance their armies. It is, nevertheless, noteworthy that the future Augustus does not volunteer members of his own immediate family to the list, although he does insist on the death of Lepidus' brother and does not object to the inclusion of Antony's nephew.
Octavius exhibits creditable insight in his observation that all who currently act friendly to the triumvirs are not indeed friends and in his attitude toward Antony throughout the play. He knows that he is in a power struggle with Antony that will intensify after they have defeated their enemies, and he knows enough about Antony's thirst for power to protect himself from domination by Antony. Consequently, he is not reluctant to disagree with Antony, as he demonstrates in his defense of Lepidus ("he's a tried and valiant soldier"), in his pointing to Antony's error in predicting that Brutus and Cassius would not come to Philippi, and in his insistence that he will fight on the right-hand side of the battlefield at Philippi and not the left-hand side as Antony orders. However, Octavius does not let his determination to remain independent interfere with following Antony's advice when he realizes that Antony speaks from experience, as he demonstrates in agreeing to allow Antony to make Lepidus a junior partner in the Triumvirate, in agreeing with Antony that the most important matter at hand following the assassination is to prepare to meet the republican armies, and in accepting Antony's decision that they should fight from defensive positions at Philippi and allow the enemy to initiate the battle.
Octavius is shrewd in his political assessments and in his relationship with Antony. He is decisive in executing the proscription and in preparing to meet Brutus and Cassius. He is also supremely confident that he will succeed in defeating his enemies at Philippi and in organizing a successful new government of Rome.