Tracy's loyal and faithful companion.
He originally belonged Tracy's neighbors, The Thompsons. After the Thompsons were murdered, Tracy took him in. Boomer was instrumental in helping her solve the mystery of his former owners' murders and several others.
At the beginning of For the Fairest, he bit her, imprinting himself on her---giving him and Tracy a special bond.
Tracy and Boomer can communicate telepathically. When she's human, his words are very rudimentary. When Tracy is a Wolf, Boomer is much clearer and articulate.