Character Analysis
Castiza is chaste, strong, and good with words. Even though we find her worrying about her poverty, she holds out against Lussurioso's offer of money in exchange for a sexual relationship. Heck, she even holds out against her own mother's encouragement to take Lussurioso's offer. Girl not only has guns, but she sticks to them, too. And luckily for us, she's a talented wordsmith, with some great dialogue. For instance, in refusal of Lussurioso's offer of wealth for sex, she sends his messenger back to him with the following message:
Tell him my honour shall have a rich name,
When several harlots shall share his with shame. (2.1.41-42)
You go, Castiza. Importantly, Castiza's one of the few characters who isn't playing a part—she's herself, for the most part, and proud of it. As we see in her refusal of Lussurioso, she has no problem standing up for herself and what she believes is right. She does test her mother, but nobody's perfect, and for the most part, Castiza's upfront and unapologetic about who she is.
For her virtue and honesty, Castiza's rewarded with a happy ending. Okay, that's an exaggeration—her brothers, Vindice and Hippolito are dead—but at least she makes up with her mom. So, you know, for a revenge tragedy, this is about as happy as endings come.