Tamora is the Queen of the Goths and one of the primary antagonists in Titus (along with her co-conspirator Aaron the Moor). She enters as a prisoner of Titus Andronicus, who has just succeeded in defeating the Goths, and, after he executes her eldest son, she swears to avenge his death by destroying Titus' family. She is one of those responsible for the rape and mutilation of Titus' daughter Lavinia; the others being Aaron, and her two remaining sons Chiron and Demetrius.

Essentially, Tamora is a 'villain' much in the vein of Joan, though she arguably begins as a more sympathetic character, a mother begging for the life of her son. She's not particularly charming or funny, and she's guilty of basically everything horrible that any one person could do (obviously, her treatment of Lavinia; also, she marries the emperor Saturninus while having an affair with Aaron and giving birth to his child, and she and Aaron engineer the deaths of two more of Titus' sons). In the end, she gets her comeuppance after Titus captures Chiron and Demetrius, kills them, bakes them into a pie, and serves said pie to Lavinia and Saturninus. After the big reveal, he kills Tamora; Saturninus kills him, and Titus' one remaining son kills Saturninus. Cheerful play, innit?

So I suppose I don't especially like her. But in terms of villains who turn everybody into the play into a morally culpable criminal of sorts, she is an excellent example.