Who is Chinja from My Soul to Keep and what is their importance?

Chinja is Mahmoud's son by a mortal woman. The woman had wanted Mahmoud to marry her, but he instead took Chinja when the child's mother told him no one would want her since she had a child. Chinja serves as Mahmoud and Dawit's servant until Mahmoud decides he has had enough of the child and abandons him.