Lune is one of Terra and Arctic's adopted pups, alongside her brother, Spottedshadow. She has her heart set on leading the Pack one day, and Terra is indeed training her to become leader in her stead. She has proven to most of the pack that she is a capable, strong wolf and enjoys the praise given to her when she does something right.
Lune leads the part of the pack known as the Patrollers, and as Terra and Arctic's adopted firstborn pup, Lune is also being primed as the heir and future leader of the Mountain Snow Pack.
Lune also has a very strong Moonsight ability, being the heir of the Mountain Snow Pack. Lune is a little jealous because of Starborn's inherently stronger Moonsight, but she pushes it aside without much difficulty. She often accompanies Terra on her trips to the Lunar Realm, to learn everything she can about it before she becomes leader.