The daughter of Brook and Pine. She and her twin brother, Flint, were the first pups to be born in the tundra.
She and Flint used to do everything together, often getting into mischief. Opal was the milder one of the two, and would often follow along with whatever her brother did. Because she and Flint are so alike, they liked to confuse their packmates over which one is who.
Although they would both initially train to hunt with their parents, Opal and Flint would end up getting into some trouble. Since Flint was blamed for it, it was decided that the siblings would have to train separately. This meant Flint would have to deal with their bitter uncle Bark in the Shards, while Opal would be terribly lonely in the Flakes without him. While Opal would grow to become a capable and serious hunter, her brother would be hardened into such an obnoxious jerk that she couldn't stand him anymore and would stop associating with him.
She has some experience with herbalism, though she ultimately decided she preferred to hunt.