Wolf's litter died, but he still has half-siblings. And it is not only Quick, but apparently there are more of his half-siblings.
"Most of Graceful's first litter thought Pup was as far beneath them as the river in the canyon. Pup knew they had never forgiven her for taking another mate- a dog! - after their own father was killed in a battle with the Far-Cliff Pack. Quick was different though."
^ Either implies that Graceful's first litter mostly died and that there are more littermates that never forgave Graceful for taking on a dog mate, therefore never talking to her.
I wonder who they are and which other wolves are related to each other.
One of the only ways to find out is to first divide the Wolf Pack into it's young wolves:
Daring and Strident both got their names on the same night, and so they must be in the same litter if they're the same age.
That leaves only Brave. On the Longpaw ranch patrol, Brave was among the pack. Even though Brave joined with Daring in being bullies towards Wolf, Wolf comments that Daring wasn't on the same patrol, and that he was glad since huntingmates needed those they could trust. I think there's a possibility that Brave is Quick's brother (therefore Wolf's half brother) or that there are more wolves unmentioned in the Wolf Pack. It almost makes sense because Wolf feels more mutual towards Brave.
Thank you for reading!