“Vengeance is in my heart, death in my hand,
Blood and revenge are hammering in my head.”
"Aaron the Moor" is Tamora's secret lover and the diabolical mastermind behind the plan to destroy the Andronicus family.
It’s pretty clear that Aaron seeks "vengeance" for something, the question, however, is this: What is it, exactly, that Aaron seeks revenge for? Does he have any real or justifiable motives? Because he wants to help his lover, Tamora, get revenge against Titus? That might be the reason, but Aaron never says much. There's got to be some better explanation. We could say that Aaron's only motive for going after the Andronicus family is that he just likes to be bad and evil.
When he says “Vengeance is in my heart” I think he means that most of the motives his actions are for “love” but not necessarily for his love over Tamora but also his love for being bad. “Death in my hand” means that he is responsible for all of the deaths and misery that he has caused. And when he says “Blood and revenge are hammering in my head” means that the thought of being evil and sadistic is always is his mind and it has become part of his life.
He is one of the main characters of the play and is shown as the principal agent of vengeance. Every bad thing that comes out in this act is a direct result of Aaron's planning or initiative. Unlike Titus and Tamora, who actually have many reasons for their actions, Aaron is all action and no motivation.
Aaron the Moor is evil incarnate, the nature of his character is ruthless with no boundaries and it has become a very important part of the events in the play. So far he is the most interesting character, so far is the most interesting character, of which I would like to know more in the remainder of the play.