Skadegemutc: Ghost Witch by Isabella Steel 

The Ghost-Witch, a demonic being born of the dead body of a shaman who chose black magic. This centuries-old evil has plagued The Two Spears and Four Claws clans for generations. Now the evil has returned, once again threatening the lives of a young mother and her twin babies. It is an evil that temporarily killed and banished with fire and magic, but it can never be destroyed. It is a source of great shame for the clans. So much so, that it is never spoken about outside of the tribe.

Maggie Four Claws, Grandma Opal, and the rest of the clans move into action to hunt down and banish the Ghost Witch but will they find the evil in time enough to destroy it and save Rebecca and her babies?