Who is Teenie from Copper Sun and what is their importance?

Teenie is a slave woman who has been working for the Derby family since she was born. As an adult, she works in the kitchen preparing all of the Derby's food. She is a kind woman, eager to pass on her slave knowledge to the younger generation of slaves. She is also very concerned with passing on her grandmother's memories of Africa to her young son, Tidbit. When Mr. Derby threatens to sell Tidbit as punishment for Teenie's behavior, Teenie poisons Mr. Derby's food and he dies.