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

Bilhah was Jacob's third wife. When Rachel was unable to bring a baby to term, Bilhah decided to sleep with Jacob, so that she can have a baby on Rachel's behalf. Bilhah has only one son, Dan. She looses the rest of her babies in childbirth. Bilhah offers Dinah a listening ear, and when she learns that Dinah is happy with Shalem, she returns to tell the rest of the family. Bilhah is described as loving, kind, and sweet.