Who is Zilpah from The Red Tent and what is their importance?

Zilpah is the last of Jacob's wives. She is given to him as a bride price for Leah. Zilpah only sleeps with Jacob, and she only goes to Jacob because Leah says that it is time. Of all the sisters, Leah and Zilpah are the closest because of their closeness in age. It is Zilpah who devises the switching of brides because she sees how much Leah and Jacob like one another. She also hated Rachel and wanted to make her unhappy.