Who is The She-Elephant from The Ear, the Eye and the Arm and what is their importance?

The only resemblance the She-Elephant has to an elephant is her enormous size. She is a heavy drinker and a ruthless master..... forcing the children to work endlessly on the underground tunnels beneath the waste dump. One thing in her favor.... she's a great cook, and the children are well fed. In the end.... the children escape..... out manuevering and out running her.