Who is Tenar from The Other Wind and what is their importance?

Tenar is Ged's wife and Tehanu's adoptive mother. Once called Priestess Arha, Tenar used to be one of the chief priestesses of the Kargad islands, and as a former Karg, she befriends the young princess Sesherrek when she is sent to King Lebannen's court. Tenar is described as a fairly short, mature woman, who has a serious but kind demeanour. She is also gifted with the ability to be straightforward, honest and compassionate at all times.