A long time ago, I read a novel? short story? about a trinity in a fantasy setting where one member is a dog, and I would really like to find it again so I could reread it. I don't remember all that much, but the beginning really stuck with me.
It starts off in a city under siege, from the perspective of a dog whose human is a wizard who has gone outside of the house for some reason. The dog can smell his? her? human outside the house, but then the smell cools and turns to meat. The dog leaves the house to look for why her? human turned to meat, and meets the second member of the trinity, who I think is a woman, but I don't remember much from there.
Edit: I don't remember the names of the characters (dog, human wizard or second member of the trinity), but it would have been in the late 80's or early 90's, and it would have been an adult story, not YA or for children. I don't believe the story went into the details of what type of magic the wizard could cast, other than it was fairly standard fantasy fare for the time. What made it memorable to me was that a significant part of the story was told from the dog's point of view.