Who is Wumeru from The Last of the Sky Pirates and what is their importance?

Wumeru is the banderbear Rook finds by a stream during his treatise-journey. Rook befriends Wumeru, and she teaches him the secret language of the banderbears. She is furious when Rook follows her to the Great Convocation of Banderbears at the Valley of a Thousand Echoes, but forgives him because he saved Wuralo at the Foundry Glade. Wumeru joins Twig's crew to save Cowlquape.