Gasparo. Thou art my task, black fury.
Zanche. I have blood
As red as either of theirs: wilt drink some?
'Tis good for the falling-sickness. I am proud:
Death cannot alter my complexion,
For I shall ne'er look pale. (The White Devil 5.6)
Above: A composite of Zipporah and Moses's Ethiopian wife from Jacob Jordaens, Moses and His Ethiopian Wife, c. 1650
The name Zanche may derive from Xanthippe, the "shrewish" wife of Socrates. The Greek "xanthe" means yellow or blonde, and may hint that Zanche is of mixed race, making her a devil in disguise too in the color symbolism of the play (cf. Toni Morrison's Playing in the Dark). "The generic name Zanche/Zanthia functions as the Jacobean stage equivalent of the American diminutive Sambo. Four out of the five bondwomen so named follow the lustful immoral prototype established by Marston in Sophonisba" (1987 article, Journal of Medieval and Renaissance Studies, vol. 17). Her skin color is frequently mentioned, of course; she is called a Moor, a witch, a gypsy. Essentially, she is not white: she is other, subaltern. At the same time, she fits well in the circle of illicit lovers, schemers, and desperate villains that surround her.
Zanche. It is a dowry,
Methinks, should make that sun-burnt proverb false,
And was the Ethiop white. (The White Devil 5.3)
Zanthia, in Marston's Wonder of Women (1606) was her prototype, the first "Moorish" waiting-woman onstage in the early modern era, and possibly the first early modern theatrical representation of a black woman, according to Anthony Gerard Bartholomy (Black Face, Maligned Race). Another black maid named Zanthia figures in Beaumont and Fletcher's Knight of Malta, although she is in opposition to her white mistress Oriana.
Mohja Kahf: "Patriarchal authority in The Knight of Malta understands Zanche's sexuality as transgressive behavior, castigating her as 'bawd,' 'devill,' 'sinfull usher'" (Western Representations of the Muslim Woman: From Termagant to Odalisque, University of Texas Press, p. 99). In Webster, I don't believe Zanche is an outlier in terms of sexuality or viciousness at all. We feel a measure of empathy for her, manipulated like Vittoria by the over-ambitious Flamineo.
"See for instance the attributes of Webster's Zanche in The White Devil, Marston's Zanthia in Sophonisba, Beaumont and Fletcher's Zanthia in The Knight of Malta, Massinger's Zanthia in The Bondmen, Rowley's Fydella in All's Lost by Lust ...(Medieval and Renaissance Drama in England, vol. 19, 2006). Incidentally, Fydella does indeed exhibit fidelity, rather than Zanche-esque rebellion and self-interest.
Although these zeta-figures are Machiavellian to varying degrees, and certainly agents of instability, Webster's Zanche is hardly the sole or primary antagonist of her community. That honor belongs to her sometime lover Flamineo. She is not an incredibly saintly character like Fydella, but she is no worse than the Europeans who surround her. I view her as a strong character struggling for survival, ill-treated by Flamineo and disinclined to yield.
The death scene where Zanche and Vittoria suddenly fire Flamineo's pistols at him and tread upon his body offers a direct use of force that had few parallels among Jacobean female characters. It also stands in direct contrast to the Duchess's physical passivity, though her maid struggles.
Black is Beautiful: Rubens to Dumas in European Art - exhibition on Dutch representations
Article by Elizabeth McGrath, "Moses and His Ethiopian Wife," Journal of the Warburg and Courtauld Institutes 70 (2007): 247-285.
Jean-Michel Massing's contribution to The Image of the Black in Western Art, the sixteenth- and seventeenth-century volumes.