Who is Merry from The Lion's Lady and what is their importance?

Merry is Christina's adoptive mother, an Indian from the Dakota tribe. She and her son had been captured by a warring band of Indians when they encountered Christina's mother, who killed the band's leader and nursed her son back to health. When Christina's mother was killed, Merry took Christina to raise as her own, promising the woman that she would send Christina back to the "white world" when she was grown. Merry faced the wrath of her husband when she arrived in the Indian village with a white child, but she stood firm in her decision to raise Christina as part of her own family and then return her.