Titus Andronicus is a very bloody tragedy with few innocent characters. Aaron the Moor, the black lover of Tamora, the Queen of the Goths, is no exception. The character Bassianus refers to him as a 'barbarous Moor' with 'foul desire' [II.iii.78-79] and by the end of that scene Bassianus has been stabbed to death and Lavinia is being dragged off to be raped and mutilated - and Aaron planned it all. In spite of Aaron's role in the violence of Titus Andronicus, Shakespeare has a way of making his audience warm to him.

Calvin Lockhart as Aaron, Margaret Tyzack as Tamora, Dir: Buzz Goodbody, RST, 1972 
 He is given a number of short soliloquies where we can see that the motivation for his actions is at least in part inspired by not wanting to be treated like a slave:

'Away with slavish weeds and servile thoughts!
I will be bright, and shine in pearl and gold
To wait upon this new-made empress.
To wait, said I? - to wanton with this queen. . . '

[II.i.18-21]

Shakespeare makes Aaron integral to the moral ambivalence of his revenge tragedy. When Aaron defends the black skin colour of his baby son from the midwife who has been ordered by Tamora, the mother, to kill him, he asks 'is black so base a hue?' [IV.ii.71] and launches into a defence of his colour and his intentions to protect his son. When Roman and Goth society is being pulled apart by fratricide and homicide, Aaron, the man who perhaps epitomises a brutal interpretation of the lines 'by all means necessary', seems to offer some hope.