By far the main character in this story is the girl the book is named for. She is called Julie (her white people name) or Miyax (her native name).
The only other real human character in my mind is Miyax's father, Kapugen. Most of the time, he is not actually seen in the story except in Julie's mind.
In my opinion, the most important characters other than Miyax herself are the wolves. I would say that there are three major wolf characters. The first is Amaroq, who is the leader of Miyax's pack. The second is the pup that she names Kapugen after her father. Finally, there is the bad guy among the wolves. His name is Jello.
To me, these are the important characters in this book.