Throughout the chapters we've read, Grace Poole has slowly become more of mysterious character. It seems as though she laughs constantly for no reason, is always by herself, and is allowed to set a fire in her master's bedroom with no consequence. Everybody at Thornfield is seemingly aware of the reason except for Jane Eyre. What is the big secret?
I have two guesses. Either she does some sort of secret job for Mr. Rochester that allows her to stay, or she's crazy but Mr. Rochester has a connection with her somehow and wants to take care of her.