What attributes of Brutus' character made the outcome of the play inevitable in Julius Caesar?

As a recap, Shakespeare's Julius Caesar ends with Cassio and Brutus, the two main assassins of Julius Caesar, meeting defeat and death on the battlefield against Octavius and Mark Antony. In many ways, Brutus' defeat is inevitable because the character's honorable moral code prevents him from succeeding in the corrupt and calculating world of Roman politics. For instance, Brutus alone works for the good of the Roman populace, striving to protect the individual political freedoms of Roman citizens. Since he is so noble, Brutus also assumes that his political companions will be accordingly honorable. Thus, Brutus' strong moral compass leaves him vulnerable to Mark Antony's manipulative rhetoric, which turns Roman opinion against Brutus, forces him into exile, and ultimately results in his death on the battlefield. Brutus could have avoided this fate by being more manipulative himself, but that wouldn't fit with his selfless character; Brutus wouldn't be Brutus without his innate nobility. As such, Brutus' admirable (and ultimately tragic) sense of honor makes his defeat and death at the end of the play inevitable.