I wondered what to call Marcus Livius Drusus, who is the most heroic and admirable character in The Grass Crown, but not the main character. When the main character is not heroic or admirable, he is called the protagonist or the anti-hero or, if you want to be long-winded, the non-hero protagonist. So the best designation I can come up with for Drusus is the non-protagonist hero.
His role in First Man in Rome was ambiguous. We first see him as a young lawyer championing an Italian who does not have Roman citizenship, and it makes us admire him. We do not admire him when he quite brutally forces his sister to marry the despised Quintus Servilius Caepio. (He marries Caepio's sister). But when he goes off to war and the army is wiped out because of his snobbish father-in-law's insubordinate conduct (he refuses to obey his military superior because he considers him a social inferior), Drusus begins the question the old order. That he is wounded and his father-in-law and brother-in-law run away while an Italian comes to his assistance opens up a breach with his in-laws and a friendship for the Italian. And when he realizes that the Italian allies didn't even know that what appeared to be incompetent generaling was actually rank insubordination, he becomes a supporter of Marius and a full-on champion of the Italians.
In The Grass Crown, Drusus emerges as the clear hero of Book II and Book IV and the non-protagonist hero of the novel as a whole. He makes up for forcing his sister to marry Caepio by leaping to her defense when her husband starts to beat her and drives his brother-in-law from his house. After his sister and her second husband die, he brings up her five children, along with his adopted son. The four middle children are not that important, but Servilia, the oldest, will become Caesar's long-term mistress and Cato, the youngest, will become Caesar's arch-enemy. And this is one that can't be blamed on an over-imaginative novelist; it actually happened in real history.
Drusus' father was a prominent conservative politician and the arch-foe of Gaius Gracchus. His tactic was to undermine Gracchus by outbidding him with measures that were not meant to pass, but only to obstruct. Thus when Gracchus proposed offering land to the poor on generous terms, the senior Drusus offered more generous terms. Incidentally, the second novel also seems to indicate that I may have been mistaken in my assessment of the Gracchi. The impression I had of Rome's popular party in general, from the Gracchi to Marius down through Caesar was that they could be described as pure left-wing populists. They championed Rome's lower classes, sought to weaken the Senate and strengthen power centers outside the Senate, and to widen citizenship. They punched up but did not kick down, and damaged their own popularity as a result. (Kicking down is popular). But this appears to be an oversimplification. The Gracchi really were, to some degree, principled against kicking down. They could easily have distributed land to Rome's poor simply by taking it from the Italians. Their unwillingness to do so appears to have been the main reason they championed Italian citizenship. Yet at the same time, the Gracchi were not immune to the temptations of kicking down. Gaius Gracchus funded his reforms by squeezing the provinces and was as hated there as he was loved in Rome.
But Drusus was the ultimate proof that things just aren't so simple. Unlike his father, he seriously proposed a program that sounded very much like the Gracchi -- distribution of individual-sized parcels of land,* cheap subsidized grain, expansion of the Senate, citizenship for all Italians. He differed from the Gracchi in that he sought to enhance the Senate's instead of weaken it and was scrupulously careful to respect Senators and not offend them. But he was the son of a prominent conservative politician and gained the support of many other conservative politicians, with the result that the popular party turned against him, even though he was enacting much of what they supported! McCullough accurately identifies his main opponents as Lucius Marcius Phillipus and Quintus Varius, and she paints both men in the most unfavorable light, but she neglects to mention that they were both leaders of the popular party.** Maybe right wing populism was more of a factor in Roman politics than I realized.
Drusus is portrayed in a most sympathetic and heroic light. Aside from protecting his sister from her abusive husband and being devoted to his wife and devastated when she dies, his championship of the Italians gets (almost) everything right. When his Italian friend proposes to illegally sign Italians up as citizens, Drusus indignantly refuses and thinks that he talks him out of it. When he finds out that the Italians are, nonetheless, illegally signing up, he splits the difference -- denounces the action, but quietly urges anyone illegally signed up to flee and escape the roving commission coming to punish them. When Marius comments that what is needed is a tribune willing to put his life on the line for the Italians, Drusus fearlessly says that he will be that tribune. As tribune fighting for the rights of the Italians, he always scrupulously follows the rules, respects the Senate, prevents violent outbreaks at his meetings, and so forth. He also plays a dangerous double game. When he visits his Italian friends, he knows they are plotting rebellion if he fails. As a patriotic Roman, he must denounce any such plans he knows of as treason, while as a loyal friend he does not want to betray them. So he visits the Italians knowing that they are plotting treason, but lets them conceal any details from him so that he does not actually have anything to reveal. He successfully passes most of the program the Gracchi fought so hard and died for. Then Phillipus scours the Italian peninsula and finds every time a misfortune occurs on the day Drusus introduced his legislation and convinces the Senate that this is a very bad omen. Drusus argues that this is really a warning about what will happen if he fails, but Philippus prevails and gets all of Drusus' legislation repealed. And although as Tribune, Drusus could veto this action, but with true statesmanship, he declines to do so. (This is historically accurate).
Drusus is not altogether without his flaws, most notably a desire for power and overconfidence. (He is also a bit manipulative, but then, he is a politician). When all the Italians swear to be his clients if admitted to citizenship, he lusts for the power this would give him. He does not desire power for its own sake, but only for what he can accomplish with it. Nonetheless, as he passes more and more legislation, he becomes intoxicated with it and has growing trouble recognizing the limits to what he can do. At the same time, he gets so caught up in his work that he forgets about the oath and, when confronted with it, he keels over, thinking that all is lost. His mother tells him that so long as he is fighting for justice, whether his motive are pure matters only to his personal vanity, and injustices are usually defeated by people who stand to gain politically as a result. Drusus seizes upon this and argues that all the Italians agreeing to be his clients is a good thing -- it ensures that they will be led by a true Roman of the Romans. He wins more and more people over to his viewpoint and is poised just on the verge of passing this crowning achievement, when he is assassinated by political opponents, in the sight of his sister's children. His last words (which McCullough gives in English and Latin, suggesting that they may be authentic) are "Who will succor Rome in my place?"
The Wikipedia describes the assassination of Drusus as "one of the main turning points in the entire series." Thinking it over, I am inclined to agree. If Drusus had lived, he would have been successful in extending citizenship to the Italians. If he had extended citizenship to the Italians, the ghastly civil war that followed could have been avoided. If Rome had not been weakened by civil war, the eastern despot Mithridates of Pontus would never have dared massacre every Roman and Italian in his domain, so there would have been no urgency in going to war with him. And if the Mithriditic War had been avoided, Marius and Sulla might have avoided their falling-out and civil war that toppled the Roman Republic.
*He did, however, differ in offering individual-sized parcels of land first to Rome's upper classes and only later to the poor, which meant that many poor men would not benefit at all. Sigh!
**Drusus' brother-in-law, Quintus Servilius Caepio was also one of his main opponents. Given his father's extraordinary snobbery about pedigree, it seems unlikely that Caepio was of the popular party.