Nothing is known about the wolf's past before she was accepted into the pack. Moonriver is the herbalist of the Cloudwhisper pack. When she had joined she had been lucky enough to gain her knowledge of herbs and healing from Ash, who had of course gained his knowledge from his estranged mother Moonset.
Moonriver is a combative wolf, always giving back handed comments to any wolf that comes in for an ailment or injury. However despite her combative, snarky nature she has a deep love for her pack- the pups especially, who she's often seen telling all sorts of stories to. Cedar, one of the pups, was noticed to have taken a rather special interest in the herbs and tools Moonriver often has at her disposal; because of this, Moonriver is planning on training Cedar to become a herbalist when she is of age.