Who is Jaada and Husniya from Midaq Alley and what is their importance?

Jaada and Husniya are husband and wife bakers whose shop is next door to Kirsha's Café, Jaada and Husniya are constantly at war with one another. Husniya rents a filthy outbuilding to Zaita, a filthy loner who earns his living by creating cripples and spends time before midnight spying through a hole in the wall on the couple as they fight and make love. When Jaada is away for the day at the baths, Zaita makes his move on Husniya and is dropped in the dust by this formidable woman.