A Wrinkle in Time
Mrs. Whatsit and IT
Both Mrs. Whatsit and IT are terrifying creatures from other worlds that turn Meg's life upside down. Both tell her to relax and not to worry. But while IT wants Meg to relax so that he can eat her brains out with a spoon, Mrs. Whatsit just wants her not to fixate on the great danger she is facing. Mrs. Whatsit and IT are both authority figures with great power, but the text makes it clear that one uses her power for good, the other for evil.